The Bad Fish Paradigm: Penny opens up to a reluctant Sheldon after a less-than-stellar first date with Leonard, putting him in the awkward position of having to keep a secret. (S2 Ep1/23) [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 Ep2/23) [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 Ep3/23) [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 Ep4/23) [AD,S]
The Jerusalem Duality: Sheldon's confidence is shaken to the core by a 15-year-old physicist who is clearly much brighter than him. (S1 Ep12/17) [AD,S]
The Bat Jar Conjecture: Sheldon is ousted from the gang's Physics Bowl quiz team, so he decides to prove his superiority by forming his own team for the event. (S1 Ep13/17) [AD,S]
The Nerdvana Annihilation: Penny makes fun of Leonard's habit of collecting goofy memorabilia, but his friends kick up a fuss and try to keep him on the side of the nerds. (S1 Ep14/17) [AD,S]
The Shiksa Indeterminacy: Leonard, Raj and Howard all fall heavily for Sheldon's twin sister, but when Leonard comes up with a plan to win her heart, it's derailed by Sheldon. (S1 Ep15/17) [AD,S]
The Peanut Reaction: Penny throws a surprise party for Leonard, with help from Howard and Raj, but Sheldon's indulgence in an electronics shop throws her off track. (S1 Ep16/17) [AD,S]
The Tangerine Factor: When Penny breaks up with her boyfriend, Leonard plucks up the courage to ask her out. And each of them turns to Sheldon for advice about their date. (S1 Ep17/17) [AD,S]
The Bad Fish Paradigm: Penny opens up to a reluctant Sheldon after a less-than-stellar first date with Leonard, putting him in the awkward position of having to keep a secret. (S2 Ep1/23) [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 Ep2/23) [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 Ep3/23) [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 Ep4/23) [AD,S]
The Positive Negative Reaction: When Bernadette makes a big announcement, Howard becomes convinced that he needs to start earning more money. (S9 Ep16/24) [AD,S]
The Celebration Experimentation: The gang persuade Sheldon to celebrate his birthday and invite a few special guests along to his party, in the 200th episode. (S9 Ep17/24) [AD,S]
The Application Deterioration: Leonard, Sheldon and Howard run into problems when they file for a patent. Emily reaches out to Raj after their break-up. (S9 Ep18/24) [AD,S]
The Solder Excursion Diversion: Sheldon makes a surprise revelation when Amy buys him a new laptop. Leonard and Howard lie to their wives to avoid an errand. (S9 Ep19/24) [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 Ep12/24) [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 Ep13/24) [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 Ep14/24) [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 Ep12/24) [AD,S]
The Locomotion Reverberation: Leonard and Howard distract Sheldon with a trip to a historic railway when he slows their progress on the guidance system. (S10 Ep15/24) [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 Ep13/24) [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 Ep14/24) [AD,S]
The Locomotion Reverberation: Leonard and Howard distract Sheldon with a trip to a historic railway when he slows their progress on the guidance system. (S10 Ep15/24) [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 Ep5/23) [AD,S]
The Cooper-Nowitzki Theorem: Sheldon's friends are mystified when a younger student is attracted to him, but her intense devotion soon becomes too much to bear. (S2 Ep6/23) [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 Ep20/24) [AD,S,W]
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,W]
The Recollection Dissipation: Sheldon collaborates on two projects - one with Leonard and Howard, plus another with Amy - pushing himself to the limit. (S10 Ep20/24) [AD,S,W]
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,W]
The Big Bear Precipitation: Sheldon shares a secret about Leonard when the two of them go on a weekend trip to a cabin in the country with Amy and Penny. (S9 Ep20/24) [AD,S]
The Viewing Party Combustion: During a get-together to watch TV at the flat, a minor argument between Sheldon and Leonard escalates into a heated debate. (S9 Ep21/24) [AD,S]
The Fermentation Bifurcation: The gang run into Penny's ex-boyfriend, Zack, at a wine bar. Bernadette, who can't drink, hangs out with Sheldon. (S9 Ep22/24) [AD,S]
The Big Bear Precipitation: Sheldon shares a secret about Leonard when the two of them go on a weekend trip to a cabin in the country with Amy and Penny. (S9 Ep20/24) [AD,S]
The Line Substitution Solution: Sheldon pays Stuart to spend the afternoon shopping with Amy so that he can queue up to see a special film screening instead. (S9 Ep23/24) [AD,S]
The Viewing Party Combustion: During a get-together to watch TV at the flat, a minor argument between Sheldon and Leonard escalates into a heated debate. (S9 Ep21/24) [AD,S]
The Fermentation Bifurcation: The gang run into Penny's ex-boyfriend, Zack, at a wine bar. Bernadette, who can't drink, hangs out with Sheldon. (S9 Ep22/24) [AD,S]
The Line Substitution Solution: Sheldon pays Stuart to spend the afternoon shopping with Amy so that he can queue up to see a special film screening instead. (S9 Ep23/24) [AD,S]
The Allowance Evaporation: Amy is furious when she learns that Sheldon has shared intimate details of their relationship with his colleagues. (S10 Ep16/24) [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 Ep17/24) [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 Ep18/24) [AD,S]
The Allowance Evaporation: Amy is furious when she learns that Sheldon has shared intimate details of their relationship with his colleagues. (S10 Ep16/24) [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 Ep19/24) [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 Ep17/24) [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 Ep18/24) [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 Ep19/24) [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 Ep7/23) [AD,S]
The Lizard-Spock Expansion: Howard is furious when a woman who he likes falls for Leonard instead, despite Howard's efforts to woo her. (S2 Ep8/23) [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,W]
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,W]
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,W]
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,W]
The Convergence Convergence: Conflict arises when Leonard's recently divorced parents and Sheldon's devoutly religious mother are all in town at the same time. (S9 Ep24/24) [AD,S]
The Conjugal Conjecture: The gang face an awkward morning after Sheldon's mother and Leonard's father share an evening together. Penny's family arrive in town. (S10 Ep1/24) [AD,S]
The Military Miniaturization: Howard has a meeting with Air Force representative Colonel Williams about the gyroscope he invented with Leonard and Sheldon. (S10 Ep2/24) [AD,S]
The Convergence Convergence: Conflict arises when Leonard's recently divorced parents and Sheldon's devoutly religious mother are all in town at the same time. (S9 Ep24/24) [AD,S]
The Dependence Transcendence: Tensions rise when the guys struggle to complete their Air Force project on time and are forced to work around the clock. (S10 Ep3/24) [AD,S]
The Conjugal Conjecture: The gang face an awkward morning after Sheldon's mother and Leonard's father share an evening together. Penny's family arrive in town. (S10 Ep1/24) [AD,S]
The Military Miniaturization: Howard has a meeting with Air Force representative Colonel Williams about the gyroscope he invented with Leonard and Sheldon. (S10 Ep2/24) [AD,S]
The Dependence Transcendence: Tensions rise when the guys struggle to complete their Air Force project on time and are forced to work around the clock. (S10 Ep3/24) [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 Ep20/24) [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 Recollection Dissipation: Sheldon collaborates on two projects - one with Leonard and Howard, plus another with Amy - pushing himself to the limit. (S10 Ep20/24) [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 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 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 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 Ep9/23) [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 Ep10/23) [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 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 Ep1/24) [AD,S]
The Dependence Transcendence: Tensions rise when the guys struggle to complete their Air Force project on time and are forced to work around the clock. (S10 Ep3/24) [AD,S]
The Military Miniaturization: Howard has a meeting with Air Force representative Colonel Williams about the gyroscope he invented with Leonard and Sheldon. (S10 Ep2/24) [AD,S]
The Conjugal Conjecture: The gang face an awkward morning after Sheldon's mother and Leonard's father share an evening together. Penny's family arrive in town. (S10 Ep1/24) [AD,S]
The Convergence Convergence: Conflict arises when Leonard's recently divorced parents and Sheldon's devoutly religious mother are all in town at the same time. (S9 Ep24/24) [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 Ep7/24) [AD,S]
The Helium Insufficiency: Sheldon and Leonard struggle to find the supplies they need for an experiment. Penny and Bernadette download a dating app for Amy. (S9 Ep6/24) [AD,S]
The Perspiration Implementation: The guys take fencing lessons from Barry Kripke. Stuart struggles to attract female customers to the comic book shop. (S9 Ep5/24) [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 Ep4/24) [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 Ep13/24) [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 Ep12/24) [AD,S]
The Line Substitution Solution: Sheldon pays Stuart to spend the afternoon shopping with Amy so that he can queue up to see a special film screening instead. (S9 Ep23/24) [AD,S]
The Fermentation Bifurcation: The gang run into Penny's ex-boyfriend, Zack, at a wine bar. Bernadette, who can't drink, hangs out with Sheldon. (S9 Ep22/24) [AD,S]
The Viewing Party Combustion: During a get-together to watch TV at the flat, a minor argument between Sheldon and Leonard escalates into a heated debate. (S9 Ep21/24) [AD,S]
The Big Bear Precipitation: Sheldon shares a secret about Leonard when the two of them go on a weekend trip to a cabin in the country with Amy and Penny. (S9 Ep20/24) [AD,S]
The Bachelor Party Corrosion: The guys' science skills are tested when they get a flat tyre during Leonard's surprise bachelor party weekend in Mexico. (S9 Ep3/24) [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 Ep2/24) [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 Ep1/24) [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 Ep24/24) [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 Ep11/24) [AD,S]
The Solder Excursion Diversion: Sheldon makes a surprise revelation when Amy buys him a new laptop. Leonard and Howard lie to their wives to avoid an errand. (S9 Ep19/24) [AD,S]
The Application Deterioration: Leonard, Sheldon and Howard run into problems when they file for a patent. Emily reaches out to Raj after their break-up. (S9 Ep18/24) [AD,S]
The Celebration Experimentation: The gang persuade Sheldon to celebrate his birthday and invite a few special guests along to his party, in the 200th episode. (S9 Ep17/24) [AD,S]
The Positive Negative Reaction: When Bernadette makes a big announcement, Howard becomes convinced that he needs to start earning more money. (S9 Ep16/24) [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 Ep23/24) [AD,S]
The Graduation Transmission: Leonard is invited to make a speech at his old high school. Howard and Sheldon can't make a toy drone fly. (S8 Ep22/24) [AD,S]
The Communication Deterioration: Raj is asked to create a message for NASA to use if one of their missions finds alien life. Penny considers taking up acting again. (S8 Ep21/24) [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 Ep20/24) [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 Ep9/24) [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 Ep8/24) [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 Ep7/24) [AD,S]
The Fetal Kick Catalyst: Penny meets her fans at a comic book convention. Sheldon and Amy host brunch at Penny's flat. Howard makes an impulsive purchase. (S10 Ep6/24) [AD,S]
The Hot Tub Contamination: Leonard and Penny intervene when Sheldon and Amy have an argument. Howard and Bernadette are disturbed by unexpected guests. (S10 Ep5/24) [AD,S]
The Cohabitation Experimentation: When Amy's flat is flooded, she has to move out while it is being repaired and proposes a 'cohabitation experiment' with Sheldon. (S10 Ep4/24) [AD,S]
The Dependence Transcendence: Tensions rise when the guys struggle to complete their Air Force project on time and are forced to work around the clock. (S10 Ep3/24) [AD,S]
The Military Miniaturization: Howard has a meeting with Air Force representative Colonel Williams about the gyroscope he invented with Leonard and Sheldon. (S10 Ep2/24) [AD,S]
The Conjugal Conjecture: The gang face an awkward morning after Sheldon's mother and Leonard's father share an evening together. Penny's family arrive in town. (S10 Ep1/24) [AD,S]
The Convergence Convergence: Conflict arises when Leonard's recently divorced parents and Sheldon's devoutly religious mother are all in town at the same time. (S9 Ep24/24) [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 Ep9/24) [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 Ep15/24) [AD,S]
The Meemaw Materialization: Sheldon is thrilled when his beloved grandmother 'Meemaw' comes to visit, but his excitement fades when she butts heads with Amy. (S9 Ep14/24) [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 Ep13/24) [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 Ep12/24) [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 Ep19/24) [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 Ep18/24) [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 Ep17/24) [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 Ep16/24) [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 Ep7/24) [AD,S]
The Fetal Kick Catalyst: Penny meets her fans at a comic book convention. Sheldon and Amy host brunch at Penny's flat. Howard makes an impulsive purchase. (S10 Ep6/24) [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 Ep11/24) [AD,S]