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) [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) [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 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) [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 Perspiration Implementation: The guys take fencing lessons from Barry Kripke. Stuart struggles to attract female customers to the comic book shop. (S9 Ep5) [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) [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 Perspiration Implementation: The guys take fencing lessons from Barry Kripke. Stuart struggles to attract female customers to the comic book shop. (S9 Ep5) [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 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) [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 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) [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 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 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 D & D Vortex: When the gang find out that Wil Wheaton is hosting a celebrity game of Dungeons & Dragons at his home, deception and betrayal take hold. (S12 Ep16) [AD,S]
The Conference Valuation: Penny and Bernadette go to San Diego for a sales convention, leaving Howard in charge of Michael and Halley while they're away. (S12 Ep17) [AD,S]
The Laureate Accumulation: When their academic competitors charm America on a publicity tour, Sheldon and Amy try to get some Nobel laureates on their side. (S12 Ep18) [AD,S]
The D & D Vortex: When the gang find out that Wil Wheaton is hosting a celebrity game of Dungeons & Dragons at his home, deception and betrayal take hold. (S12 Ep16) [AD,S]
The Inspiration Deprivation: Amy has a meltdown when she feels the pressure of what it would mean for women everywhere if she were to win a Nobel Prize. (S12 Ep19) [AD,S]
The Conference Valuation: Penny and Bernadette go to San Diego for a sales convention, leaving Howard in charge of Michael and Halley while they're away. (S12 Ep17) [AD,S]
The Laureate Accumulation: When their academic competitors charm America on a publicity tour, Sheldon and Amy try to get some Nobel laureates on their side. (S12 Ep18) [AD,S]
The Inspiration Deprivation: Amy has a meltdown when she feels the pressure of what it would mean for women everywhere if she were to win a Nobel Prize. (S12 Ep19) [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) [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) [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 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 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 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 Nerdvana Annihilation: When Penny makes fun of Leonard's habit of collecting goofy memorabilia, his friends kick up a fuss and try to keep him on the side of the nerds. (S1 Ep14) [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) [AD,S]
The Nerdvana Annihilation: When Penny makes fun of Leonard's habit of collecting goofy memorabilia, his friends kick up a fuss and try to keep him on the side of the nerds. (S1 Ep14) [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) [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 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 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 Decision Reverberation: Raj publishes a paper that suggests he may have discovered alien life. Penny encourages Leonard to stand up for himself. (S12 Ep20) [AD,S]
The Plagiarism Schism: Barry Kripke finds proof that Dr Pemberton plagiarised his thesis in college. Should Sheldon and Amy turn in their rival? (S12 Ep21) [AD,S]
The Maternal Conclusion: Leonard is surprised when his mother Beverly comes to visit and is kind to him, until he finds out the real reason she's there. (S12 Ep22) [AD,S]
The Decision Reverberation: Raj publishes a paper that suggests he may have discovered alien life. Penny encourages Leonard to stand up for himself. (S12 Ep20) [AD,S]
The Change Constant: Sheldon and Amy stay up late awaiting a phone call that could bring big news from the Nobel Committee: are their lives about to change? (S12 Ep23) [AD,S]
The Plagiarism Schism: Barry Kripke finds proof that Dr Pemberton plagiarised his thesis in college. Should Sheldon and Amy turn in their rival? (S12 Ep21) [AD,S]
The Maternal Conclusion: Leonard is surprised when his mother Beverly comes to visit and is kind to him, until he finds out the real reason she's there. (S12 Ep22) [AD,S]
The Change Constant: Sheldon and Amy stay up late awaiting a phone call that could bring big news from the Nobel Committee: are their lives about to change? (S12 Ep23) [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) [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) [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) [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) [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) [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 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 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) [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 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) [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 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) [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 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) [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 Stockholm Syndrome: Howard and Bernadette go on a trip without their children, Leonard and Penny try to keep a secret, and Raj makes a new friend. (S12 Ep24) [AD,S]
Pilot: The first ever episode of the hit sitcom. Leonard and Sheldon's geeky world is shaken up by the arrival of a beautiful new neighbour. (S1 Ep1) [AD,S]
The Stockholm Syndrome: Howard and Bernadette go on a trip without their children, Leonard and Penny try to keep a secret, and Raj makes a new friend. (S12 Ep24) [AD,S]
The Fuzzyboots Corollary: Leonard is upset when he discovers that Penny is seeing someone, so he plucks up the courage to ask a woman out on a date. (S1 Ep3) [AD,S]
Pilot: The first ever episode of the hit sitcom. Leonard and Sheldon's geeky world is shaken up by the arrival of a beautiful new neighbour. (S1 Ep1) [AD,S]
The Fuzzyboots Corollary: Leonard is upset when he discovers that Penny is seeing someone, so he plucks up the courage to ask a woman out on a date. (S1 Ep3) [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 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 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 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 Decision Reverberation: Raj publishes a paper that suggests he may have discovered alien life. Penny encourages Leonard to stand up for himself. (S12 Ep20) [AD,S]
The Wedding Gift Wormhole: A stressed Sheldon and Amy struggle to work out what the 'perfect gift' is that Leonard and Penny gave them on their wedding day. (S12 Ep2) [AD,S]
The Conjugal Configuration: Sheldon and Amy's honeymoon runs aground, while Penny and Leonard discover that they are uncomfortably similar to Amy's parents. (S12 Ep1) [AD,S]
The Bow Tie Asymmetry: Everyone is focused on making sure that the arrangements for Amy and Sheldon's big day go according to plan - except the bride and groom. (S11 Ep24) [AD,S]
The Sibling Realignment: When Sheldon finds out that his mum won't come to his wedding unless he invites his brother Georgie, he and Leonard head to Texas. (S11 Ep23) [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 D & D Vortex: When the gang find out that Wil Wheaton is hosting a celebrity game of Dungeons & Dragons at his home, deception and betrayal take hold. (S12 Ep16) [AD,S]
The Monetary Insufficiency: Sheldon goes to Las Vegas to try to win money for science. Penny and Bernadette take Amy shopping for a wedding dress. (S11 Ep22) [AD,S]
The Comet Polarization: Sheldon isn't pleased by the comic book shop's new-found popularity. Raj tries to take the credit for Penny's astronomical discovery. (S11 Ep21) [AD,S]
The Reclusive Potential: A brilliant scientist invites Sheldon to his isolated cabin, and Leonard, Raj and Howard go along for the trip. (S11 Ep20) [AD,S]
The Tenant Disassociation: Leonard competes with Sheldon to become president of the tenants' association. Howard and Raj find a drone in the back garden. (S11 Ep19) [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]
The Anxiety Optimization: When Sheldon gets stuck in a rut with his research, he asks his friends to cure his mental block by raising his stress levels. (S8 Ep13) [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) [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) [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 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 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 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]
The Anxiety Optimization: When Sheldon gets stuck in a rut with his research, he asks his friends to cure his mental block by raising his stress levels. (S8 Ep13) [AD,S]
The Donation Oscillation: Penny attempts to sabotage Leonard's efforts to help her ex-boyfriend Zack and his wife Marissa have a family of their own. (S12 Ep15) [AD,S]
The Meteorite Manifestation: Sheldon is thrilled to help Howard and Bernadette with some bureaucratic paperwork, until he realises that they're breaking the law. (S12 Ep14) [AD,S]
The Confirmation Polarization: Sheldon and Amy are thrilled when their super-asymmetry theory is proved correct. Bernadette enjoys some big success at work. (S12 Ep13) [AD,S]
The Propagation Proposition: Penny's ex-boyfriend Zack and his wife want a baby, but when they encounter fertility problems, they ask Leonard for his help. (S12 Ep12) [AD,S]
The Gates Excitation: The guys do everything in their power to meet Bill Gates when his firm has dealings with the pharmaceutical company Penny works for. (S11 Ep18) [AD,S]
The Athenaeum Allocation: Leonard jumps through hoops to secure the perfect wedding venue for Sheldon and Amy. Howard and Bernadette face a big decision. (S11 Ep17) [AD,S]
The Novelization Correlation: Amy appears on the Professor Proton show. Penny hates the idea that the female protagonist in Leonard's novel is based on her. (S11 Ep15) [AD,S]
The Space Probe Disintegration: Howard tries to calm a stressed Raj, who is anxiously awaiting the arrival of some data from a space probe that he helped launch. (S8 Ep12) [AD,S]
The Clean Room Infiltration: Amy hosts a Victorian Christmas Eve dinner, complete with party games. Raj, Leonard and Howard have pigeon problems. (S8 Ep11) [AD,S]
The Paintball Scattering: Jealousy, trust issues and tension among the couples in the gang cause mayhem when Penny and Leonard organise a paintball game. (S12 Ep11) [AD,S]
The VCR Illumination: Sheldon and Amy are still upset about their theory being disproven, but a video tape from Sheldon's past inspires him not to give up. (S12 Ep10) [AD,S]
The Citation Negation: Sheldon and Amy get some devastating news. Bernadette asks Stuart's girlfriend Denise to teach her how to beat Howard at a video game. (S12 Ep9) [AD,S]
The Grant Allocation Derivation: Leonard is made responsible for distributing extra grant money. Bernadette turns the garden playhouse into a hideaway to escape her family. (S12 Ep7) [AD,S]
The Separation Triangulation: Raj gets into a domestic drama with his new date Nell and her estranged husband. Sheldon rents his old room back from Leonard. (S11 Ep14) [AD,S]
The Solo Oscillation: Amy and Leonard bond over some experiments. Bert replaces Howard in his band. Penny gives Sheldon unexpected scientific inspiration. (S11 Ep13) [AD,S]
The Matrimonial Metric: Sheldon and Amy secretly test their friends, to work out who should be best man and maid of honour at their wedding. (S11 Ep12) [AD,S]
The Celebration Reverberation: Sheldon and Howard plan birthday celebrations for Amy and Halley. Leonard is stressed by a Christmas letter from his brother. (S11 Ep11) [AD,S]
The Champagne Reflection: Sheldon and Amy record the final episode of their internet show Fun with Flags. Penny tells Bernadette how her colleagues really feel about her. (S8 Ep10) [AD,S]
The Septum Deviation: When Leonard has to have minor surgery on his nose, Sheldon is the one who seems to need sympathy. Raj is upset when his parents split up. (S8 Ep9) [AD,S]
The Procreation Calculation: Stuart starts bringing his new girlfriend home to Howard and Bernadette's house. Penny and Leonard talk about starting a family. (S12 Ep3) [AD,S]
The Bitcoin Entanglement: Sheldon seeks revenge when the guys cut him out of a potentially valuable investment. A secret about Leonard and Penny is revealed. (S11 Ep9) [AD,S]
The Tesla Recoil: Leonard and Howard learn that Sheldon went to work with the military behind their backs. Bernadette thinks Ruchi's trying to steal her job. (S11 Ep8) [AD,S]
The Geology Methodology: Sheldon and Bert collaborate on a research project, but Sheldon feels embarrassed to be associated with the study of geology. (S11 Ep7) [AD,S]
The Prom Equivalency: The girls decide to re-enact their high school proms with their current partners on the roof of the apartment building. (S8 Ep8) [AD,S]