When Amy’s apartment floods, she proposes a “cohabitation experiment” with Sheldon. Meanwhile, Howard and Bernadette are upset when Raj learns the gender of their baby before they do.
Tensions rise when the guys struggle to complete their government project on time – and Sheldon tries an energy drink to stay awake. Also, Penny and Amy go to a “party” at the house of Bert, the ge...
In the tenth season premiere, Penny’s family arrives for the wedding ceremony, including her anxiety-ridden mother, Susan (guest star KATEY SAGAL), her drug-dealing brother, Randall (guest star JAC...
The stars and creative team of The Big Bang Theory celebrate the recipients of the new "Big Bang Theory Scholarship" which awards students pursuing degrees in STEM fields, featuring behind the scen...
Chaos ensues in the ninth season finale when Leonard’s recently divorced parents (special guest stars JUDD HIRSCH and CHRISTINE BARANSKI) and Sheldon’s devoutly religious mother come to town. Meanw...
Sheldon hires Stuart to spend the day with Amy when he’d rather go to a movie screening. Also, Leonard’s mother, Beverly, comes to town and Penny struggles to make a connection with her.
The gang goes to a wine bar and runs into Penny’s old boyfriend, Zack (recurring guest star BRIAN THOMAS SMITH); Bernadette gets stuck spending the evening with Sheldon when she can’t go wine tasti...
Sheldon spills a secret of Leonard’s when the two take a weekend cabin trip with Penny and Amy; Meanwhile Howard and Bernadeitte must draw the line when Raj goes overboard with pregnancy gifts.
In the series premiere, when Leonard and Sheldon meet Penny, Leonard is immediately interested in her. But Sheldon feels his friend is chasing a dream he'll never catch.
As Wolowitz contemplates taking things with Bernadette to the next level, he must choose between his girlfriend and his mother. Meanwhile, Leonard rekindles his relationship with Raj's sister, Priya.
After Leonard tries to do a favor for Penny, Sheldon ruins the plan. Leonard volunteers to sign for a package, hoping to make a good impression on Penny. However, when he involves his obsessive-com...
On the second season finale, Leonard and Penny reconsider their feelings for one another. When Leonard and his friends decide to spend the summer working -- at the North Pole -- Penny is conflicted.
In the third season finale, Wolowitz and Koothrappali search for Sheldon's perfect match online -- and find Sheldon's ideal woman (guest star MAYIM BIALIK). Meanwhile, Penny worries that dating Leo...
Leonard attends a co-worker's wedding as Amy's date. Meanwhile, Howard tries to convince Bernadette to live with his mom after they get married by suggesting a trial run with the two of them stayin...
A battle of wills between Sheldon and Penny leaves Amy caught in the middle, while Leonard tries to spice up his long-distance relationship with Priya (recurring guest star AARTI MANN), who has mov...
Sheldon wants Penny to give him acting lessons, hoping that they will help him become a better teacher. Meanwhile, Koothrappali fantasizes about his best friend's girlfriend.
The gang celebrates Halloween at Stuart's comic book store. Meanwhile Leonard and Penny discover a new spark in their relationship when he seduces her with science. And while Howard can't stop talk...
When Sheldon realizes he won't live long enough to download his consciousness into a robot body, he attempts to extend his lifespan. Apple Co-Founder STEVE WOZNIAK guest stars as Himself.
Suffering from a case of "physicist's block," Sheldon's search for the answer to a physics problem leads him to work at the Cheesecake Factory with Penny.