The Cooper Extraction: Sheldon has to go back to Texas when his sister goes into labour. While he's away, the gang gather at the flat to decorate the Christmas tree. (S7 Ep11) [AD,S]
The Cooper Extraction: Sheldon has to go back to Texas when his sister goes into labour. While he's away, the gang gather at the flat to decorate the Christmas tree. (S7 Ep11) [AD,S]
The Codpiece Topology: Seeing Penny out on a date with another guy sends a distressed Leonard rushing back to Leslie Winkle, much to Sheldon's dismay. (S2 Ep2) [AD,S]
The Barbarian Sublimation: Penny becomes addicted to an online game based on the world of Conan the Barbarian and begins to pester Sheldon for advice. (S2 Ep3) [AD,S]
The Cognition Regeneration: Leonard isn't happy when he finds out that Penny is considering accepting a job offer from her ex-boyfriend Zack. (S10 Ep22/24) [AD,S]
The Separation Agitation: Howard and Bernadette are upset when they leave Halley at the nursery. Bert the geologist introduces his girlfriend to the gang. (S10 Ep21/24) [AD,S]
The Cognition Regeneration: Leonard isn't happy when he finds out that Penny is considering accepting a job offer from her ex-boyfriend Zack. (S10 Ep22/24) [AD,S]
The Wildebeest Implementation: Raj attempts to overcome his anxiety about talking to women, while Penny uses Bernadette to spy on Leonard and his girlfriend. (S4 Ep22) [AD,S]
The Engagement Reaction: Howard finally tells his mother that he's engaged to Bernadette. Unfortunately, the news lands his mum in hospital. (S4 Ep23) [AD,S]
The Roommate Transmogrification: Raj decides to move in with Sheldon after hearing Leonard and Priya engaging in a Star Trek bedroom fantasy. (S4 Ep24) [AD,S]
The Wildebeest Implementation: Raj attempts to overcome his anxiety about talking to women, while Penny uses Bernadette to spy on Leonard and his girlfriend. (S4 Ep22) [AD,S]
The Skank Reflex Analysis: Penny worries that she's screwed things up with her friends after her night with Raj. Sheldon takes command of the paintball team. (S5 Ep1) [AD,S]
The Engagement Reaction: Howard finally tells his mother that he's engaged to Bernadette. Unfortunately, the news lands his mum in hospital. (S4 Ep23) [AD,S]
The Roommate Transmogrification: Raj decides to move in with Sheldon after hearing Leonard and Priya engaging in a Star Trek bedroom fantasy. (S4 Ep24) [AD,S]
The Skank Reflex Analysis: Penny worries that she's screwed things up with her friends after her night with Raj. Sheldon takes command of the paintball team. (S5 Ep1) [AD,S]
The Werewolf Transformation: Sheldon's well-organised world is turned upside down when he learns that the barber who has cut his hair for years is ill in hospital. (S5 Ep18) [AD,S]
The Weekend Vortex: Amy is upset when Sheldon breaks his promise to attend her aunt's birthday party in order to join the guys for a Star Wars video game marathon instead. (S5 Ep19) [AD,S]
The Transporter Malfunction: Penny buys Leonard and Sheldon some Star Trek memorabilia, but she is irked when they refuse to remove the toys from their packaging. (S5 Ep20) [AD,S]
The Hawking Excitation: When Stephen Hawking comes to lecture at the university, Howard is given the task of maintaining his wheelchair, which makes Sheldon envious. (S5 Ep21) [AD,S]
The Work Song Nanocluster: Penny's home-based business selling hair accessories gets out of hand when an overexcited Sheldon takes charge of production. (S2 Ep18) [AD,S]
The Dead Hooker Juxtaposition: Penny develops a rivalry with a sexy female neighbour who moves into the apartment building and threatens to become the 'new Penny'. (S2 Ep19) [AD,S]
The Hofstadter Isotope: Leonard is devastated when Stuart from the comic book shop chats up Penny. Even worse, she doesn't mind. Sheldon tries to scupper the budding romance. (S2 Ep20) [AD,S]
The Vegas Renormalization: Leonard and Raj take a heartbroken Howard to Las Vegas, leaving Sheldon locked out of his flat and forced to stay with Penny. (S2 Ep21) [AD,S]
The Occupation Recalibration: Penny quits her job at the restaurant to pursue her acting career full-time. Bernadette accidentally destroys one of Howard's comics. (S7 Ep13) [AD,S]
The Convention Conundrum: After the guys miss out on Comic-Con tickets, Sheldon decides to hold his own comic book convention. The girls take tea at a swanky hotel. (S7 Ep14) [AD,S]
The Occupation Recalibration: Penny quits her job at the restaurant to pursue her acting career full-time. Bernadette accidentally destroys one of Howard's comics. (S7 Ep13) [AD,S]
The Convention Conundrum: After the guys miss out on Comic-Con tickets, Sheldon decides to hold his own comic book convention. The girls take tea at a swanky hotel. (S7 Ep14) [AD,S]
The Cooper-Hofstadter Polarization: Sheldon and Leonard fall out when they're asked to collaborate at a physics conference. Penny tries to help but just makes things worse. (S1 Ep9) [AD,S]
The Cooper-Hofstadter Polarization: Sheldon and Leonard fall out when they're asked to collaborate at a physics conference. Penny tries to help but just makes things worse. (S1 Ep9) [AD,S]
The Occupation Recalibration: Penny quits her job at the restaurant to pursue her acting career full-time. Bernadette accidentally destroys one of Howard's comics. (S7 Ep13) [AD,S]
The Occupation Recalibration: Penny quits her job at the restaurant to pursue her acting career full-time. Bernadette accidentally destroys one of Howard's comics. (S7 Ep13) [AD,S]
The Griffin Equivalency: Full of confidence after being named one of People magazine's '30 to Watch Under 30', Raj hits on Penny and becomes impossibly arrogant. (S2 Ep4) [AD,S]
The Euclid Alternative: When Leonard can't drive Sheldon to and from work, the friends stage an intervention to overcome Sheldon's fear of getting behind the wheel. (S2 Ep5) [AD,S]
The Gyroscopic Collapse: Amy is offered a fellowship at Princeton, Raj makes new living arrangements, and the guys' gyroscope project spins out of control. (S10 Ep23/24) [AD,S]
The Long Distance Dissonance: The gang worry when Sheldon's former admirer, Dr Ramona Nowitzki, turns up while Amy is away working at Princeton. (S10 Ep24/24) [AD,S]
The Gyroscopic Collapse: Amy is offered a fellowship at Princeton, Raj makes new living arrangements, and the guys' gyroscope project spins out of control. (S10 Ep23/24) [AD,S]
The Long Distance Dissonance: The gang worry when Sheldon's former admirer, Dr Ramona Nowitzki, turns up while Amy is away working at Princeton. (S10 Ep24/24) [AD,S]
The Infestation Hypothesis: Amy is stuck in the middle of a battle of wills between Penny and Sheldon. Leonard and Priya try to spice up their long-distance relationship. (S5 Ep2) [AD,S]
The Pulled Groin Extrapolation: Leonard goes to a colleague's wedding as Amy's date. Howard tries to convince Bernadette to live with his mum after they get married. (S5 Ep3) [AD,S]
The Wiggly Finger Catalyst: Raj begins to get upset that he's the only one of the four guys not in a relationship, so Penny sets out to find him the perfect date. (S5 Ep4) [AD,S]
The Infestation Hypothesis: Amy is stuck in the middle of a battle of wills between Penny and Sheldon. Leonard and Priya try to spice up their long-distance relationship. (S5 Ep2) [AD,S]
The Russian Rocket Reaction: Sheldon's old nemesis Wil Wheaton returns and invites everyone to a housewarming party. But Sheldon threatens to 'de-friend' Leonard if he attends. (S5 Ep5) [AD,S]
The Pulled Groin Extrapolation: Leonard goes to a colleague's wedding as Amy's date. Howard tries to convince Bernadette to live with his mum after they get married. (S5 Ep3) [AD,S]
The Wiggly Finger Catalyst: Raj begins to get upset that he's the only one of the four guys not in a relationship, so Penny sets out to find him the perfect date. (S5 Ep4) [AD,S]
The Russian Rocket Reaction: Sheldon's old nemesis Wil Wheaton returns and invites everyone to a housewarming party. But Sheldon threatens to 'de-friend' Leonard if he attends. (S5 Ep5) [AD,S]
The Stag Convergence: Leonard, Sheldon and Raj throw a bachelor party for Howard, during which some stories about his sexual history are accidentally revealed. (S5 Ep22) [AD,S]
The Launch Acceleration: When NASA inform Howard that his space mission has been rescheduled to an earlier date, he tries to use the wedding as an excuse not to go. (S5 Ep23) [AD,S]
The Countdown Reflection: Bernadette decides that she wants to get married to Howard before his NASA space mission, but can they get organised in time? (S5 Ep24) [AD,S]
The Stag Convergence: Leonard, Sheldon and Raj throw a bachelor party for Howard, during which some stories about his sexual history are accidentally revealed. (S5 Ep22) [AD,S]
The Date Night Variable: Howard gets caught in a row between his mum and Bernadette while he's at the International Space Station. Sheldon invites Raj along on a date with Amy. (S6 Ep1) [AD,S]
The Launch Acceleration: When NASA inform Howard that his space mission has been rescheduled to an earlier date, he tries to use the wedding as an excuse not to go. (S5 Ep23) [AD,S]
The Countdown Reflection: Bernadette decides that she wants to get married to Howard before his NASA space mission, but can they get organised in time? (S5 Ep24) [AD,S]
The Date Night Variable: Howard gets caught in a row between his mum and Bernadette while he's at the International Space Station. Sheldon invites Raj along on a date with Amy. (S6 Ep1) [AD,S]
The Classified Materials Turbulence: Things look up for Leonard when Penny makes a surprising revelation on her second date with Stuart. Howard sees a flaw in his NASA project. (S2 Ep22) [AD,S]
The Monopolar Expedition: Leonard and Penny reconsider their feelings for each other, but then Leonard is offered the opportunity to spend the summer working at the North Pole. (S2 Ep23) [AD,S]
The Electric Can Opener Fluctuation: Leonard's attempts to woo Penny are constantly thwarted. Sheldon heads to Texas after learning his friends meddled with his expedition data. (S3 Ep1) [AD,S]
The Jiminy Conjecture: Leonard and Penny feel awkward around each other after their romantic liaison, while Sheldon and Howard take bets to determine a species of cricket. (S3 Ep2) [AD,S]
The Locomotive Manipulation: Love is in the air when Amy convinces Sheldon to join her for a romantic train trip to Napa Valley to celebrate Valentine's Day. (S7 Ep15) [AD,S]
The Table Polarization: Leonard buys a dining table for the flat but Sheldon objects to such a big change inside his home. Meanwhile, Howard gets the chance to return to space. (S7 Ep16) [AD,S]
The Locomotive Manipulation: Love is in the air when Amy convinces Sheldon to join her for a romantic train trip to Napa Valley to celebrate Valentine's Day. (S7 Ep15) [AD,S]
The Table Polarization: Leonard buys a dining table for the flat but Sheldon objects to such a big change inside his home. Meanwhile, Howard gets the chance to return to space. (S7 Ep16) [AD,S]
The Locomotive Manipulation: Love is in the air when Amy convinces Sheldon to join her for a romantic train trip to Napa Valley to celebrate Valentine's Day. (S7 Ep15) [AD,S]
The Locomotive Manipulation: Love is in the air when Amy convinces Sheldon to join her for a romantic train trip to Napa Valley to celebrate Valentine's Day. (S7 Ep15) [AD,S]
The Proposal Proposal: Amy must decide whether or not to marry Sheldon and gives him an answer to his proposal. Howard and Bernadette struggle with some unexpected news. (S11 Ep1) [AD,S]
The Retraction Reaction: Leonard angers the university during an embarrassing interview. Amy and Bernadette must hide their success from Sheldon and Howard. (S11 Ep2) [AD,S]
The Relaxation Integration: Amy tries to convince Sheldon that he has a more laid-back side. Raj and Stuart compete to woo Bernadette's new colleague Ruchi. (S11 Ep3) [AD,S]
The Proposal Proposal: Amy must decide whether or not to marry Sheldon and gives him an answer to his proposal. Howard and Bernadette struggle with some unexpected news. (S11 Ep1) [AD,S]
The Explosion Implosion: Howard and Sheldon bond on a trip to the desert to launch a model rocket. Leonard is annoyed when his mother befriends Penny. (S11 Ep4) [AD,S]
The Retraction Reaction: Leonard angers the university during an embarrassing interview. Amy and Bernadette must hide their success from Sheldon and Howard. (S11 Ep2) [AD,S]
The Relaxation Integration: Amy tries to convince Sheldon that he has a more laid-back side. Raj and Stuart compete to woo Bernadette's new colleague Ruchi. (S11 Ep3) [AD,S]
The Explosion Implosion: Howard and Sheldon bond on a trip to the desert to launch a model rocket. Leonard is annoyed when his mother befriends Penny. (S11 Ep4) [AD,S]
The Cooper-Nowitzki Theorem: Sheldon's friends are mystified when a younger student is attracted to him, and her intense devotion soon becomes too much to bear. (S2 Ep6) [AD,S]
The Panty PiÄnata Polarization: Sheldon bans Penny from the flat for numerous minor infractions, so she retaliates. Howard and Raj search for the America's Next Top Model house. (S2 Ep7) [AD,S]
The White Asparagus Triangulation: Sheldon is delighted that Leonard has finally found a girlfriend who matches up to his high standards... Perhaps a little too delighted. (S2 Ep9) [AD,S]
The Vartabedian Conundrum: Leonard goes to Penny for help when his relationship with Stephanie takes off faster than he'd like, but will he act on her advice? (S2 Ep10) [AD,S]
The Bath Item Gift Hypothesis: At Christmas, Leonard's hunky colleague starts dating Penny, while Sheldon's obsession with gift-giving etiquette torments everyone. (S2 Ep11) [AD,S]
The Killer Robot Instability: Kripke challenges the boys to a robot duel, while Howard is devastated when Penny finally tells him what she thinks of his chauvinism. (S2 Ep12) [AD,S]
The Friendship Algorithm: Sheldon develops a scientific procedure for making friends when he discovers that Kripke has control of a new supercomputer at the university. (S2 Ep13) [AD,S]
The Financial Permeability: When Sheldon lends Penny some money, it brings her ex-boyfriend Kurt back into her life, with negative consequences for the gang. (S2 Ep14) [AD,S]
The Romance Resonance: Sheldon is mortified when he stumbles upon an important scientific breakthrough by accident. Howard makes a romantic gesture to Bernadette. (S7 Ep6) [AD,S]
The Russian Rocket Reaction: Sheldon's old nemesis Wil Wheaton returns and invites everyone to a housewarming party. But Sheldon threatens to 'de-friend' Leonard if he attends. (S5 Ep5) [AD,S]
The Wiggly Finger Catalyst: Raj begins to get upset that he's the only one of the four guys not in a relationship, so Penny sets out to find him the perfect date. (S5 Ep4) [AD,S]
The Pulled Groin Extrapolation: Leonard goes to a colleague's wedding as Amy's date. Howard tries to convince Bernadette to live with his mum after they get married. (S5 Ep3) [AD,S]
The Infestation Hypothesis: Amy is stuck in the middle of a battle of wills between Penny and Sheldon. Leonard and Priya try to spice up their long-distance relationship. (S5 Ep2) [AD,S]
The Boyfriend Complexity: When Penny's father visits, Leonard discovers that her parents still think that he and Penny are a couple, so he takes advantage of the situation. (S4 Ep9) [AD,S]
The 21-Second Excitation: The gang's plans to attend a film screening are scuppered by Sheldon's nemesis Wil Wheaton. Penny and Bernadette invite Amy to her first slumber party. (S4 Ep8) [AD,S]
The Apology Insufficiency: Leonard thinks his dating problems are due to a lack of confidence, and vows to be self-assured around attractive women. Howard is called by the FBI. (S4 Ep7) [AD,S]
The Irish Pub Formulation: A visit from Raj's sister Priya creates tension among the guys, especially when Leonard asks Sheldon to conceal his romantic past with her. (S4 Ep6) [AD,S]
The Emotion Detection Automation: Sheldon tests a new invention after hearing that it could help him to read people's emotions. Raj seeks dating advice. (S10 Ep14) [AD,S]
The Romance Recalibration: Penny thinks that Leonard has stopped making an effort in their relationship, so she decides to go away for a spa weekend with Amy. (S10 Ep13) [AD,S]
The Raiders Minimization: Amy ruins one of Sheldon's favourite films by pointing out a flaw in the storyline. Raj and Stuart decide to create online dating profiles. (S7 Ep4) [AD,S]
The Scavenger Vortex: Raj organises an epic and demanding scavenger hunt, designed to test the friends' scientific knowledge and common sense. (S7 Ep3) [AD,S]
The Skank Reflex Analysis: Penny worries that she's screwed things up with her friends after her night with Raj. Sheldon takes command of the paintball team. (S5 Ep1) [AD,S]
The Roommate Transmogrification: Raj decides to move in with Sheldon after hearing Leonard and Priya engaging in a Star Trek bedroom fantasy. (S4 Ep24) [AD,S]
The Engagement Reaction: Howard finally tells his mother that he's engaged to Bernadette. Unfortunately, the news lands his mum in hospital. (S4 Ep23) [AD,S]
The Wildebeest Implementation: Raj attempts to overcome his anxiety about talking to women, while Penny uses Bernadette to spy on Leonard and his girlfriend. (S4 Ep22) [AD,S]
The Desperation Emanation: Leonard realises he's the only one of the gang with no girlfriend. Sheldon wants to get rid of his when she hatches a plan for him to meet her mother. (S4 Ep5) [AD,S]
The Hot Troll Deviation: An embarrassing secret of Howard's comes to light as he tries to win back Bernadette. Sheldon and Raj have trouble working together. (S4 Ep4) [AD,S]
The Zazzy Substitution: The guys are concerned when a heartbroken Sheldon starts bulk buying cats after he breaks up with Amy, so Leonard tries to get Sheldon's mother to visit. (S4 Ep3) [AD,S]
The Cruciferous Vegetable Amplification: Sheldon realises that he won't live long enough to download his consciousness into a robot body, so he tries to extend his lifespan. (S4 Ep2) [AD,S]
The Holiday Summation: After spending Christmas apart, the gang gather at Penny and Leonard's flat and hear about Sheldon and Amy's terrible trip to Texas. (S10 Ep12) [AD,S]
The Birthday Synchronicity: Sheldon and Amy try to celebrate her birthday with an intimate night at home but are interrupted when Bernadette goes into labour. (S10 Ep11) [AD,S]
The Deception Verification: Leonard returns early from his research expedition as a surprise for Penny, but Sheldon becomes upset that he wasn't in on the secret. (S7 Ep2) [AD,S]
The Hofstadter Insufficiency: Sheldon and Penny bond while Leonard is away. Raj finds someone to share his heartache. Bernadette and Amy attract male attention at a conference. (S7 Ep1) [AD,S]
The Agreement Dissection: Priya uses her legal expertise to dissect the roommate agreement and put Sheldon in his place, and the girls take Sheldon dancing. (S4 Ep21) [AD,S]
The Herb Garden Germination: Sheldon and Amy experiment on their friends by spreading gossip, while Howard takes a big step in his relationship with Bernadette. (S4 Ep20) [AD,S]
The Zarnecki Incursion: When somebody hacks into Sheldon's online gaming account, he and his friends become determined to locate the culprit. (S4 Ep19) [AD,S]
The Prestidigitation Approximation: Leonard must choose between his new girlfriend Priya and his friendship with Penny. Howard drives Sheldon crazy with a magic trick. (S4 Ep18) [AD,S]
The Robotic Manipulation: Penny tags along to Sheldon's first date with a woman he's been texting for months. Howard finds a new use for a robotic arm. (S4 Ep1) [AD,S]
The Lunar Excitation: Raj registers Sheldon for online dating and finds the perfect match: the female version of Sheldon. Penny seduces Leonard while she's drunk. (S3 Ep23) [AD,S]
The Plimpton Stimulation: When Sheldon meets a famous physicist online, he invites her over to the apartment, where she spends her time flirting with Leonard. (S3 Ep21) [AD,S]
The Geology Elevation: Sheldon can't contain his jealousy when he hears that his university colleague, Bert the geologist, has won a prestigious fellowship. (S10 Ep9) [AD,S]
The Bon Voyage Reaction: Leonard is offered an exciting job opportunity that will keep him out of the country for several months. Raj pushes the boundaries of his relationship. (S6 Ep24) [AD,S]
The Love Spell Potential: When the girls' trip to Las Vegas falls through, the guys invite them to a Dungeons & Dragons night that changes Sheldon and Amy's relationship. (S6 Ep23) [AD,S]
The Toast Derivation: Sheldon is surprised and disturbed to find out that it's really Leonard who is at the centre of their group of friends and not him. (S4 Ep17) [AD,S]
The Cohabitation Formulation: Howard is torn between taking things to the next level with Bernadette and pleasing his mother. Leonard rekindles his relationship with Priya. (S4 Ep16) [AD,S]
The Benefactor Factor: A wealthy benefactor at the university makes Leonard consider how far he's willing to go in the name of science. (S4 Ep15) [AD,S]
The Thespian Catalyst: Sheldon lectures at the university but worries that the students don't seem to like him. Raj fantasises about his best friend's girlfriend. (S4 Ep14) [AD,S]
The Spaghetti Catalyst: Sheldon hides his friendship with Penny from Leonard, but it isn't long before his double life is exposed. Can he remain friends with both of them? (S3 Ep20) [AD,S]
The Wheaton Recurrence: Leonard tells Penny that he loves her. The gang go bowling and find that Sheldon's enemy, Wil Wheaton, is playing in the opposing team. (S3 Ep19) [AD,S]
The Pants Alternative: Sheldon is awarded a prestigious prize but is scared of collecting the award at a ceremony because he knows he'll have to make a speech. (S3 Ep18) [AD,S]
The Precious Fragmentation: The gang squabble over a ring that they believe was used in The Lord of the Rings movies, and Sheldon seems to be turning into Gollum. (S3 Ep17) [AD,S]
The Brain Bowl Incubation: Sheldon tries to convince Amy that they should procreate. Raj feels embarrassed about what the new woman in his life does for a living. (S10 Ep8) [AD,S]
The Veracity Elasticity: Leonard is upset when he finds out that Penny has been moving his collectables out of Sheldon's old room and into storage behind his back. (S10 Ep7) [AD,S]
The Proton Resurgence: Leonard and Sheldon hire Professor Proton, the host of a TV science show they watched as children, to come to their flat and entertain them. (S6 Ep22) [AD,S]
The Closure Alternative: Amy employs a series of exercises to cure Sheldon of his compulsion to complete every task without fail and seek closure for every incident. (S6 Ep21) [AD,S]