The Big Bang Theory, Season 8

On the eighth season premiere, Leonard and Amy take an unexpected road trip to Arizona to pick up Sheldon. Meanwhile, Penny interviews for a job at Bernadette’s company.

When Sheldon is forced to teach a class, Howard surprises everyone by taking it. Meanwhile, the tension between Penny and Bernadette gives Amy a chance to play both sides. Guest star Regina King returns as Mrs. Davis, the University's Director of Employee Relations.

Howard is nervous when NASA asks him to throw out the first pitch at a Los Angeles Angels game for National Space Day. Also, Leonard and Penny try to prove Sheldon wrong after he claims that he and Amy are a superior couple.

Raj's honesty about his past comes back to bite him after his girlfriend is cold to Penny. Meanwhile, the guys consider becoming part-owners in Stuart's comic-book store.

Amy and Bernadette accuse Penny of being a "buzzkill" after she gets an email from work during their Vegas weekend. Meanwhile, the guys try to invent something cool, but only come up with new ways to procrastinate.

Sheldon and Raj test whether they could survive a dark-matter research expedition in a salt mine by simulating the conditions in a steam tunnel deep underground. Meanwhile, Leonard and Penny seek advice from Wolowitz and Bernadette after they fight about money.

The guys try to help Penny out of an awkward work dilemma, when a smitten doctor shows up at her door after her flirtatious sales techniques work a little too well. Meanwhile, Amy and Bernadette argue over whether or not female scientists should play up their sexuality.

When the gang recreates a high-school prom night on the roof of the guys'; apartment building, Sheldon feels pressure to participate in all the typical romantic traditions.

When Leonard gets minor surgery on his nose, Sheldon is the one in need of sympathy. Meanwhile, Raj's parents' impending divorce causes Howard and Bernadette to work on their own marriage.

While Sheldon says a tearful goodbye to the final installment of "Fun with Flags", Leonard, Howard and Raj search for something significant in a dead professor's research. And Bernadette is shocked to learn of her co-workers’ true feelings from Penny.

Leonard and Howard turn to Raj for help in dealing with a work emergency when they nearly come to blows after blaming each other for a potential disaster at the university. Amy throws an authentic Victorian Christmas party, while Sheldon seeks revenge on her for making him celebrate the holidays.

When the guys finally agree to do something the girls like, it leads to a confrontation between Leonard and Sheldon.

In the hopes of achieving a scientific breakthrough, Sheldon invites his friends to challenge him and make him miserable. Meanwhile, Wolowitz invents an embarrassing game about Raj.

After Leonard and Sheldon co-publish a physics paper, they must defend themselves against criticism from an online bully. Also, girls' night finds Penny, Amy and Bernadette confronting embarrassing moments from their pasts.

Howard receives some shocking news as everyone prepares for the reopening of Stuart's comic book store. Penny teaches Sheldon how to "let it go" but can't follow her own advice after she learns something infuriating about Amy. Also, Leonard and Raj think they spot Nathan Fillion at a restaurant.

When the gang hears about an experiment designed to make participants fall in love, Sheldon and Penny put it to the test as a joke. Meanwhile, Leonard, Amy, Raj and Emily spend the evening trying to escape a room with a "zombie." And Bernadette and Howard run into trouble at the airport after returning from the funeral for Mrs. Wolowitz.

A trip to the pet store ends in a fight when Amy learns that Sheldon has applied for a one-way mission to colonize Mars. Also, Leonard surprises Penny with a very "adult" purchase; and Raj is caught snooping in Emily's apartment.

Friction ensues when a magazine fails to mention Leonard in an article about the paper he co-wrote with Sheldon. And a blackout at Mrs. Wolowitz's home leads to a final family dinner in her honor.

When Leonard and Sheldon are invited to speak at UC Berkeley, they take a detour to try to sneak on to George Lucas's Skywalker Ranch to meet one of their idols. Back in Pasadena, Howard and Bernadette battle over the fate of his Dr. Who Tardis, while Raj and Amy offer to settle the dispute with a game of ping pong.

Howard finds out that he has a half-brother, Sheldon and Amy have a G-rated sleepover and Penny gets an offer to audition for a Kevin Smith movie.

When Raj is asked to create a message in case a NASA mission discovers alien life, the guys fight over what he should do. Meanwhile, Penny is torn between auditioning for a movie or keeping her successful pharmaceutical sales job.

Leonard is asked to make the commencement address at his old high school. Raj splurges on a robotic helicopter which Sheldon and Howard want to use.

Personalities collide and sparks fly when Sheldon and Leonard's mothers (special guest stars Laurie Metcalf and Christine Baranski) finally meet. Meanwhile, Howard decides to "man up" and do his fair share of the housework – but not without a little help from his friends.

In the eighth season finale, Sheldon presses Leonard and Penny to choose a date for their wedding, while dealing with dramatic changes in his own relationship with Amy.

Series director Mark Cendrowsi takes the audience on a guided tour of the non-stop action he and the cast endure every week while filming The Big Bang Theory.

The executive producers, writers and cast reveal what's coming in Season 8.

A tribute in memory of the late Carol Ann Susi.

Gag Reel

Behind the scenes of Billy Bob Thornton’s guest starring role.

A documentary about the search for the world's biggest BBT Superfans and their trip to LA to meet the cast and crew on set.