Brilliant physicist roommates Leonard and Sheldon meet their new neighbor Penny, who begins showing them that as much...

Leonard volunteers to sign for a package in an attempt to make a good impression on Penny, but when he enlists Sheldo...

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...

Fearing he's wasting his time on Penny, Leonard ends up making a connection with Leslie.

Penny hosts a Halloween party, putting Leonard, Sheldon, Wolowitz, and Koothrappali through a new test of their socia...

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 bet...

Leonard and Sheldon each lie to avoid seeing Penny's concert, but Sheldon's is a bit too complicated for his own good.

With his friends knowing how sour he acts when sick—and avoiding him as a result—Sheldon is nursed by Penny, who hasn...

With Sheldon rattled over meeting Dennis, a 15-year-old physicist who's smarter than he, Leonard helps him look for a...

Sheldon finds himself booted from the gang's Physics Bowl team and replaced with Leslie, so he forms his own team, ho...

When delivery of another collectible leads to Penny's lashing out at Leonard, he decides it's time to give up his hab...

The rest of the gang fall for Sheldon's twin sister, and Leonard's plan to win her heart is derailed when Sheldon dec...

Penny wants to throw a surprise party for Leonard, but Sheldon's indulgence at an electronics store throws her off-tr...

Penny's break-up spurs Leonard to summon the courage to ask her out, and each goes to Sheldon for advice on their upc...