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

Sheldon’s getting fired forces him to explore what life has to offer outside physics, leaving Leonard to take drastic action to snap his friend out of his funk.

Penny hosts a Halloween 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

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’t a clue what she’s in for.

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

Sheldon finds himself booted from the gang’s Physics Bowl team and replaced with Leslie, so he forms his own team, hoping to prove he’s superior.

Leonard volunteers to sign for a package in an attempt to make a good impression on Penny, but when he enlists Sheldon for help, his attempt at chivalry goes terribly…

Leonard asks a woman out after he finds out that Penny is seeing someone.