A new success for Leonard makes Sheldon very jealous and throws Penny for a loop. Meanwhile, Koothrappali pushes Lucy too far in their relationship. (TV-PG L)
When the girls' trip to Vegas falls through, the guys invite them to play Dungeons & Dragons, causing Sheldon and Amy's relationship to take an unexpected turn. Meanwhile, Koothrappali and Lucy go on a very awkward date. (TV-PG D, L)
Sheldon and Leonard hire Professor Proton, the host of their favorite childhood TV show, to perform. Also, Howard and Bernadette run into trouble babysitting Raj's dog. Bob Newhart guest stars as Professor Proton. (TV-PG L)
Sheldon feels lost after one of his favorite TV shows gets canceled too soon and Amy tries to help him get over his compulsive need for closure. Meanwhile, Raj discovers a secret about his new love interest. (TV-PG D, L)
Amy feels threatened when Sheldon hires a young female assistant, and the pressure of being in space takes its toll on Wolowitz. (TV-PG D)
Penny is shocked that Raj actually opens up to her and shares his feelings over Lucy ending things.
After hearing how worried Lucy is about meeting the gang Amy agrees to meet her and discuss her own experience.
Raj would like nothing more than for Lucy to accompany him to a party and meet his friends.
Sheldon interrupts Leonard and Penny's long goodbye.
The girls gear up for a fabulous trip to Vegas while the boys prepare for some serious Dungeons and Dragons fun.
Raj confronts Lucy about her constant leaving but the two end up finally kissing.
Amy injures a TSA agent preventing the girls from flying to Vegas so the guys invite them to play with them.
Amy finally asks Sheldon if he has any interest in being intimate with her. His answer surprises her.
Bob Newhart guest stars as Professor Proton.
Professor Proton has some trouble with his pacemaker and Sheldon accompanies him to the hospital.
Sheldon and Leonard are ecstatic to learn that their childhood television idol is still around and can be hired for an appearance.
Professor Proton tries to understand why two grown Physicists want him to put on a children's show for them.
Sheldon and Leonard explain to Professor Proton how valuable his show was to young scientists.
Get all caught up on The Big Bang Theory with our CBS Season Rewind recap! Don't miss the season finale, Thursday, May 16th, 8/7 c. Only CBS!
Sheldon finds out that his favorite show has been canceled so he decides to call the television station that produces it.