
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?

When the guys agree to do something the girls like, Sheldon and Leonard end up having a confrontation.

Howard and Raj hit a Goth nightclub to meet women; Sheldon tries chocolate-based behavior modification on Penny.

Sheldon asks his friends to challenge him in hope of achieving a scientific breakthrough; Wolowitz invents a game about Raj.

When Penny and Bernadette go to San Diego for a pharmaceutical sales convention, Wolowitz is left in charge of the kids; Sheldon finds a book about experimenting on kids.