Penny: Leonard, you're back.
Leonard: Yeah, I just stopped by to say… [Penny grabs Leonard and kisses him] Yeah, so, hi!
Penny: Hi! [They stumble into her apartment while kissing]

Penny: At one point, they had me figure out how to get a banana out of a puzzle box.
Leonard: Wait, Sheldon gave me a banana in a box. He was testing me, too.
Penny: Unbelievable.
Leonard: And how could a chimp even solve that? That was impossible.
Penny: Really? You couldn't get it out?

Leonard: If I take it off, Sheldon wins.
Penny: Sweetie, every night you don't kill him in his sleep, he wins.

Sheldon: Woman, you are playing with forces beyond your ken.
Penny: Yeah, well your Ken can kiss my Barbie.

Howard: Sheldon, you remember the first few weeks we were looking for magnetic monopoles and not finding anything, and you were acting like an obnoxious, giant dictator?
Raj: I thought we were going to be gentle with him.
Howard: That's why I added the '-tator'.

Sheldon: Hello, Penny. I realize you are currently in the mercy of your primitive biological urges. But, as you have an entire lifetime of poor decisions ahead of you, may I interrupt this one?

Sheldon: But evolution is not opinion, it's a fact.
Mary Cooper: And that is your opinion.
Sheldon: [to Leonard, Howard and Raj] I forgive you, let's go home.