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 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 Meemaw Materialization: Sheldon is thrilled when his beloved grandma 'Meemaw' comes to visit, but his excitement fades when she butts heads with Amy. (S9 Ep14) [AD,S]
The Valentino Submergence: Sheldon and Amy host a special live Valentine's Day episode of their internet show Fun with Flags. Leonard and Penny grapple with getting older. (S9 Ep15) [AD,S]
The Positive Negative Reaction: When Bernadette makes a big announcement, Howard becomes convinced that he needs to start earning more money. (S9 Ep16) [AD,S]
The Meemaw Materialization: Sheldon is thrilled when his beloved grandma 'Meemaw' comes to visit, but his excitement fades when she butts heads with Amy. (S9 Ep14) [AD,S]
The Valentino Submergence: Sheldon and Amy host a special live Valentine's Day episode of their internet show Fun with Flags. Leonard and Penny grapple with getting older. (S9 Ep15) [AD,S]
The Positive Negative Reaction: When Bernadette makes a big announcement, Howard becomes convinced that he needs to start earning more money. (S9 Ep16) [AD,S]
The Spock Resonance: While he's being interviewed for a documentary about Star Trek character Mr Spock, Sheldon can't suppress his emotions about his split from Amy. (S9 Ep7) [AD,S]
The Mystery Date Observation: While Amy's out on a date with a mystery man, Sheldon enlists Howard and Raj to help him find a new girlfriend online. (S9 Ep8) [AD,S]
The Spock Resonance: While he's being interviewed for a documentary about Star Trek character Mr Spock, Sheldon can't suppress his emotions about his split from Amy. (S9 Ep7) [AD,S]
The Mystery Date Observation: While Amy's out on a date with a mystery man, Sheldon enlists Howard and Raj to help him find a new girlfriend online. (S9 Ep8) [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 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 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 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 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 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 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 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 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 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 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 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 Allowance Evaporation: Amy is furious when she learns that Sheldon has shared intimate details of their relationship with his colleagues. (S10 Ep16) [AD,S]
The Comic-Con Conundrum: Cut off from his father's fortune, Raj appoints Sheldon to organise his finances. Penny considers joining the guys at Comic-Con. (S10 Ep17) [AD,S]
The Platonic Permutation: At Thanksgiving, Sheldon and Amy hang out as friends at the aquarium, and Howard reluctantly agrees to volunteer at a soup kitchen. (S9 Ep9) [AD,S]
The Earworm Reverberation: Sheldon is driven to distraction when he can't get a familiar tune out of his head. Howard and Raj find out that their band has a fan. (S9 Ep10) [AD,S]
The Platonic Permutation: At Thanksgiving, Sheldon and Amy hang out as friends at the aquarium, and Howard reluctantly agrees to volunteer at a soup kitchen. (S9 Ep9) [AD,S]
The Earworm Reverberation: Sheldon is driven to distraction when he can't get a familiar tune out of his head. Howard and Raj find out that their band has a fan. (S9 Ep10) [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 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 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 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 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 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 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 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 Escape Hatch Identification: Leonard and Penny offer Sheldon's old room to Raj when he's forced to move out of his flat, leading to unexpected conflict. (S10 Ep18) [AD,S]
The Collaboration Fluctuation: Leonard, Penny and Raj settle into their new living arrangement, and Sheldon expresses an interest in Amy's professional life. (S10 Ep19) [AD,S]
The Opening Night Excitation: Leonard, Howard and Raj have an extra ticket for the Star Wars movie premiere but can't decide who they should give it to. (S9 Ep11) [AD,S]
The Sales Call Sublimation: Penny gets more than she bargained for when Leonard meets a psychiatrist, while Sheldon and Raj make an astronomical discovery. (S9 Ep12) [AD,S]
The Opening Night Excitation: Leonard, Howard and Raj have an extra ticket for the Star Wars movie premiere but can't decide who they should give it to. (S9 Ep11) [AD,S]
The Sales Call Sublimation: Penny gets more than she bargained for when Leonard meets a psychiatrist, while Sheldon and Raj make an astronomical discovery. (S9 Ep12) [AD,S]
The Alien Parasite Hypothesis: Amy realises that she has romantic feelings for Zack. Raj and Howard compete to prove who would make the better superhero. (S4 Ep10) [AD,S]
The Justice League Recombination: The guys slowly warm to Zack and find an enjoyable way to bond with him when they enter a New Year's Eve fancy dress competition together. (S4 Ep11) [AD,S]
The Alien Parasite Hypothesis: Amy realises that she has romantic feelings for Zack. Raj and Howard compete to prove who would make the better superhero. (S4 Ep10) [AD,S]
The Justice League Recombination: The guys slowly warm to Zack and find an enjoyable way to bond with him when they enter a New Year's Eve fancy dress competition together. (S4 Ep11) [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 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 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 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 Recollection Dissipation: Sheldon collaborates on two projects - one with Leonard and Howard, plus another with Amy - pushing himself to the limit. (S10 Ep20) [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 Empathy Optimization: The gang plan a Sheldon-free weekend in Las Vegas after coping with his constant demands, rudeness and ingratitude when he was ill. (S9 Ep13) [AD,S]
The Meemaw Materialization: Sheldon is thrilled when his beloved grandma 'Meemaw' comes to visit, but his excitement fades when she butts heads with Amy. (S9 Ep14) [AD,S]
The Empathy Optimization: The gang plan a Sheldon-free weekend in Las Vegas after coping with his constant demands, rudeness and ingratitude when he was ill. (S9 Ep13) [AD,S]
The Meemaw Materialization: Sheldon is thrilled when his beloved grandma 'Meemaw' comes to visit, but his excitement fades when she butts heads with Amy. (S9 Ep14) [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 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 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 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 Rhinitis Revelation: Sheldon's mother Mary comes to town and soon becomes a firm favourite with his friends, much to Sheldon's annoyance. (S5 Ep6) [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 Rhinitis Revelation: Sheldon's mother Mary comes to town and soon becomes a firm favourite with his friends, much to Sheldon's annoyance. (S5 Ep6) [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 Justice League Recombination: The guys slowly warm to Zack and find an enjoyable way to bond with him when they enter a New Year's Eve fancy dress competition together. (S4 Ep11) [AD,S]
The Alien Parasite Hypothesis: Amy realises that she has romantic feelings for Zack. Raj and Howard compete to prove who would make the better superhero. (S4 Ep10) [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 Separation Oscillation: Sheldon films a special post-break-up episode of Fun with Flags. Bernadette feels guilty about withholding a secret from Penny. (S9 Ep2) [AD,S]
The Matrimonial Momentum: Penny struggles with Leonard's confession that he kissed another woman. Sheldon doesn't know how to act when Amy breaks up with him. (S9 Ep1) [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 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 Excelsior Acquisition: Sheldon is summoned to court for driving through a red light. He misses the chance to meet Stan Lee and riles the judge. Will he go to prison? (S3 Ep16) [AD,S]
The Large Hadron Collision: Sheldon is gutted when Leonard asks Penny to go to Switzerland on Valentine's Day to see the world's largest particle accelerator instead of him. (S3 Ep15) [AD,S]
The Commitment Determination: Sheldon pressures Leonard and Penny to choose a date for their wedding while dealing with changes in his own relationship. (S8 Ep24) [AD,S]
The Maternal Combustion: Personalities collide when Sheldon and Leonard's mothers finally meet. Howard decides to 'man up' and do his share of the housework. (S8 Ep23) [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 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 2003 Approximation: Sheldon sulks when Penny and Leonard announce that they're moving in together. Howard and Raj form a band to play at the comic book shop. (S9 Ep4) [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 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 Maternal Congruence: Leonard is horrified when his mother turns up unannounced for a Christmas visit, and then he finds out that Sheldon knew about her divorce before him. (S3 Ep11) [AD,S]
The Vengeance Formulation: Howard is scared about committing to Bernadette, so he avoids her. Then he realises that he's made a mistake and, to compensate, he proposes to her. (S3 Ep9) [AD,S]
The Fortification Implementation: When Sheldon and Amy build a blanket fort, they come to a major crossroads in their relationship. Howard meets his half-brother. (S8 Ep20) [AD,S]
The Skywalker Incursion: When Leonard and Sheldon are invited to speak at Berkeley, they take a detour during the journey to try to meet one of their idols. (S8 Ep19) [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 Staircase Implementation: Leonard tells Penny about how he and Sheldon became friends, and the origins of the roommate agreement. (S3 Ep22/23) [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 Ep21/23) [AD,S]
The Adhesive Duck Deficiency: Leonard, Raj and Howard go on a camping trip that alters their minds. Penny dislocates her shoulder when she slips in the shower. (S3 Ep8) [AD,S]
The Guitarist Amplification: Sheldon is annoyed when Leonard and Penny argue about Penny's male friend staying over and he has to act as peacemaker. (S3 Ep7) [AD,S]
The Cornhusker Vortex: Sheldon teaches Leonard about American football so that he can try to fit in with Penny's friends. And Raj and Sheldon have a kite-fighting contest. (S3 Ep6) [AD,S]
The Leftover Thermalization: A power cut at Mrs Wolowitz's house defrosts the last meal she prepared before her death, so the gang consume it in her honour. (S8 Ep18) [AD,S]
The Colonization Application: Amy learns that Sheldon has applied to take part in a one-way mission to colonise Mars. Leonard surprises Penny with a gift. (S8 Ep17) [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 Creepy Candy Coating Corollary: Due to a childhood snub, Sheldon is irked when Star Trek actor Wil Wheaton (guest starring as himself) takes part in the same contest as him. (S3 Ep5) [AD,S]
The Pirate Solution: Raj must find a job or he'll be sent back to India, so he accepts an offer of work from Sheldon. Leonard and Penny try to get some time for themselves. (S3 Ep4) [AD,S]
The Gothowitz Deviation: Sheldon tries to modify Penny's behaviour, and rewards her with chocolate when she does what he wants, while Howard and Raj go to a goth nightclub. (S3 Ep3) [AD,S]
The Intimacy Acceleration: When the gang hear about an experiment designed to make participants fall in love, Sheldon and Penny put it to the test as a joke. (S8 Ep16) [AD,S]
The Comic Book Store Regeneration: The gang prepare for the reopening of Stuart's comic book shop. Penny teaches Sheldon to 'let it go' when he is irritated. (S8 Ep15) [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 Excelsior Acquisition: Sheldon is summoned to court for driving through a red light. He misses the chance to meet Stan Lee and riles the judge. Will he go to prison? (S3 Ep16) [AD,S]
The Large Hadron Collision: Sheldon is gutted when Leonard asks Penny to go to Switzerland on Valentine's Day to see the world's largest particle accelerator instead of him. (S3 Ep15) [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 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 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 Troll Manifestation: Leonard and Sheldon co-publish a physics paper but are forced to defend themselves against negative comments from an online critic. (S8 Ep14) [AD,S]