The Proton Displacement
Season 7, Ep. 7
When Professor Proton asks Leonard for help with an experiment, Sheldon retaliates by befriending Proton's rival, Bill Nye.
READ: It's Bill Nye the Science Guy vs. Professor Proton, played by Bob Newhart
First Aired: November 7, 2013
The Romance Resonance
Season 7, Ep. 6
Sheldon's latest scientific breakthrough leaves him feeling like a fraud; a romantic gesture between Howard and Bernadette causes Penny to up her game with Leonard.
First Aired: October 24, 2013
The Workplace Proximity
Season 7, Ep. 5
Sheldon and Amy's relationship is tested when she takes a job at his university; a fight with Bernadette leaves Howard sleeping on Raj's couch.
First Aired: October 17, 2013
The Raiders Minimization
Season 7, Ep. 4
Sheldon wants revenge after Amy ruins one of his favorite films; Leonard finds a way to get Penny to do anything; Stuart and Raj make online dating profiles.
Read more: 'Raiders of the Lost Ark' meets 'BBT' meets Sheldon's wrath
First aired: October 10, 2013
The Scavenger Vortex
Season 7, Ep. 3
Raj designs a scavenger hunt that brings out the best -- and the worst -- in the whole gang.
READ: Raj unleashes 'Big Bang' demons as he plans a scavenger hunt for the gang
First aired: Oct. 3, 2013
The Deception Verification
Season 7, Ep. 2
Sheldon and Penny share intimate secrets while Leonard is away at sea, later, Sheldon's feelings are crushed when Leonard returns. Meanwhile, Raj gets consoled about his ex-girlfriend and Wolowitz's relationship with his mother causes an unusual threat to his masculinity.
First Aired: Sept. 26, 2013
The Hofstadter Insufficiency
Season 7, Ep. 1
Sheldon and Penny share secrets while Leonard is away; Wolowitz helps Raj get over his ex.
READ: Season 7 premiere: Jealousy (no!) babies and trouble in paradise
First Aired: Sept. 26, 2013
The Bon Voyage Reaction (Finale)
Season 6, Ep. 24
When Leonard receives an exciting opportunity to work overseas, Penny and Sheldon are thrown for a loop.
'BBT' finale: Sheldon gets jealous over Leonard's new job, and it might not be happily-ever-after with Raj and Lucy 'Spock'-tacular: The cast can't get enough 'Star Trek' on 'BBT'
The Love Spell Potential
Season 6, Ep. 23
Amy and Sheldon's relationship takes a surprising turn during a game of "Dungeons & Dragons"; Lucy and Koothrappali have an awkward date.
Read more: Will Sheldon and Amy actually talk about that thing they've been avoiding?
Gallery: Love is in the air on 'BBT'
First Aired: May 9, 2013
The Proton Resurgence
Season 9, Ep. 22
Leonard and Sheldon hire the host (Bob Newhart) of their favorite childhood TV show to perform; Bernadette and Howard run into trouble while dog-sitting for Raj's pet.
Read more: Sheldon meets his childhood idol on ‘Big Bang Theory’ but ends up riding with him to the hospital
First Aired: May 2, 2013
The Closure Alternative
Season 6, Ep. 21
Amy tries to help Sheldon get over his compulsive need for closure when one of his favorite TV shows is canceled; Raj discovers a secret about Lucy.
First Aired: April 25, 2013
The Tenure Turbulence
Season 6, Ep. 20
The girls get involved when Leonard, Sheldon and Raj compete for tenure at the University.
First Aired: April 4, 2013
The Closet Reconfiguration
Season 6, Ep. 19
Howard considers whether or not he should open a letter from his father; Penny and Leonard host a "grown-up" cocktail party.
Read more: You’re invited to a 'Big Bang Theory' dinner party
Read even more: Cast celebrates success of past 4 years, but withholds spoilers
First Aired: March 14, 2013
The Contractual Obligation Implementation
Season 6, Ep. 18
Leonard, Sheldon and Wolowitz talk to junior high girls about science-related careers; Raj plans a date with Lucy.
Read more: The guys head back to junior high, while Raj tries to sweep Lucy off her feet
Gallery: Forget the lab or the couch, the cast of 'BBT' hits the red carpet
First aired on March 7, 2013.
The Monster Isolation
Season 6, Ep. 17
Raj is put out when his date walks out in the middle of their evening, so he vows that he will forever stay put in his apartment. Meanwhile, Sheldon is quite impressed when he witnesses Penny's acting skills firsthand.
Read more: Love was in the air...but maybe not for Raj
First aired on February 21, 2013.
The Cooper/Kripke Inversion
Season 6, Ep. 14
Sheldon faces a crisis of confidence when he is forced to work with his nemesis, Barry Kripke; Raj and Howard buy expensive action figures of themselves.
Read: My 88-year-old 'Meemaw's' love of 'Big Bang Theory'
First aired on January 31, 2013.
The Bakersfield Expedition
Season 6, Ep. 13
As the guys don costumes and go on a road trip to a comic book convention, the ladies decide to stay home and try to interpret a comic book.
First aired on January 10, 2013
The Egg Salad Equivalency
Season 6, Ep. 12
When Sheldon is accused of sexual harassment, he ends up getting Raj, Leonard and Wolowitz in trouble.
First aired on January 3, 2013.
The Santa Simulation
Season 6, Ep. 11
Sheldon has issues with Santa Claus on Christmas.
First aired on December 13, 2012.
The Fish Guts Displacement
Season 6, Ep. 10
Amy takes ill and Sheldon becomes her nursemaid, while Wolowitz takes a fishing trip in order to bond with his father-in-law.
First aired December 5, 2012.
The Parking Spot Escalation
Season 6, Ep. 9
Sheldon and Wolowitz's fight over a parking spot at the university impacts the whole gang.
First aired on November 29, 2012.
The 43 Peculiarity
Season 6, Ep. 8
Raj and Howard try to figure out why Sheldon disappears at 2:45 every afternoon; jealousy arises in Penny and Leonard's relationship.
First aired on November 15, 2012.
The Habitation Configuration
Season 6, Ep. 7
Bernadette wants Wolowitz to move out of his mom's house; Sheldon is caught in the middle of Amy and Wil Wheaton's argument.
First aired on November 8, 2012.