Brilliant physicist roommates Leonard and Sheldon meet their new neighbor Penny.
Leonard volunteers to sign for a package in an attempt to make a good impression on Penny.
Leonard asks a woman out after he finds out that Penny is seeing someone.
Sheldon's getting fired forces him to explore what life has to offer outside physics, leaving Leonard to take drastic action.
Fearing he's wasting his time on Penny, Leonard ends up making a connection with Leslie.
Penny hosts a Hallowe'en party, putting Leonard, Sheldon, Wolowitz, and Koothrappali through a new test of their social skills.
With Wolowitz AWOL with one of her friends, Penny's recruited to fill in for him on the guys' Halo team
Raj's parents set him up on a blind date, but just when he discovers he can talk to her, she shows interest in Sheldon.
When they're invited to present at a physics conference, Sheldon's reluctance to share the credit leads to a tiff between him and Leonard.
Sheldon and Leonard lie to avoid seeing Penny perform.
Sheldon gets sick and Penny has to deal with him.
The boys try to derail a young physics prodigy's research.
Sheldon's nemesis (SARA GILBERT) takes his spot in a match.
The guys buy a time machine; Penny disapproves.
The boys all become smitten with Sheldon's twin sister.
Penny attempts to throw Leonard a wild surprise party.
Leonard finds the courage to ask Penny out on a real date.