
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?

Leonard is horrified when his mother (Christine Baranski) visits.

The gang runs into Penny's old boyfriend while out at a wine bar; Bernadette spends an evening with Sheldon; Koothrappali's introduction of his new girlfriend doesn't go as planned.

Leonard is happy to meet new neighbor Penny, but his roommate thinks he is chasing an impossible dream.

Sheldon wants to go to a movie screening, so he pays Stuart to spend the day with Amy; Penny has a difficult time connecting with Leonard's visiting mother.