Ep 21. The Plimpton Stimulation

In season 3 episode 21 of The Big Bang Theory titled "The Plimpton Stimulation," the gang is excited when a famous physicist, Dr. Elizabeth Plimpton (played by guest star Judy Greer), comes to Caltech to conduct research with Sheldon. While Sheldon is thrilled to work with such a renowned scientist, he quickly becomes jealous of the attention she is receiving from his friends and even Penny.

As they set up their experiments, Sheldon finds himself increasingly attracted to Plimpton, causing tension between them. Meanwhile, Leonard and Raj try to score an invitation to a party hosted by a former cast member of Firefly, but they struggle to think of a way to get in.

As the episode progresses, tensions between Sheldon and Plimpton continue to rise, leading to a memorable confrontation between the two. Leonard and Raj eventually come up with a plan to attend the Firefly party, leading to some hilarious hijinks along the way.

In the end, the gang learns some valuable lessons about jealousy, competition, and pushing beyond their comfort zones to pursue new opportunities. With its trademark blend of nerdy humor and heart, "The Plimpton Stimulation" is a classic episode of The Big Bang Theory that fans won't want to miss.