Sheldon tries to help Penny understand Leonard's work; Wolowitz gets jealous when Leonard starts hanging out with his new girlfriend.

After being humiliated on the radio, Sheldon vows to destroy Kripke; Wolowitz tries to not ruin his new relationship with Bernadette.

Penny is forced to rely on Sheldon when she is injured while Howard, Leonard and Raj are away.

Sheldon tries to make peace when Leonard and Penny get into an argument.

Sheldon teaches Leonard how to understand football; a kite-fighting incident threatens Howard and Raj's friendship.

Sheldon seeks revenge on his nemesis, Wil Wheaton; Wolowitz wants Penny to set him up with one of her friends.

Raj faces deportation if he does not find a job; Leonard and Penny deal with Howard as a third wheel.

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

Penny and Leonard try to recover from an awkward hookup; Howard and Sheldon make a high-stakes bet.

After tampering with Sheldon's Arctic-expedition data, the guys follow him back to Texas, which threatens Leonard's chances for romance with Penny.