
Mensa-fied best friends and roommates Leonard and Sheldon, physicists who work at the California Institute of Technology, may be able to tell everybody more than they want to know about quantum physics, but getting through most basic social situations, especially ones involving women, totally baffles them. How lucky, then, that babe-alicious waitress/aspiring actress Penny moves in next door. Frequently seen hanging out with Leonard and Sheldon are friends and fellow Caltech scientists Wolowitz and Koothrappali. Will worlds collide? Does Einstein theorize in the woods?

Amy and Leonard try to help Sheldon deal with his shame; Raj stays with Bernadette and Howard for a week.

While Sheldon is in Texas, the rest of the gang realize how much he has changed their lives as they decorate the apartment Christmas tree.

As Leonard tries to help Penny with a disappointment, Penny asks him a bold question about their relationship; Sheldon wants to learn how to be funny.

Sheldon must learn how to relax when he is forced to take a vacation; Leonard tries to support Penny when she quits her job; Bernadette needs to replace one of Stuart's comic books.