Penny: Is this your only tie?
Leonard: Ah. Technically yes, but, if you'll notice, it's reversible. So it works as two.
Penny: Oh, sweetie, I don't think it even works as one.

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

Leonard: What am I supposed to do?
Penny: Err, keep your mouth off other women.

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

Leonard: Is this the stuff you want me to try on?
Penny: No this is the stuff I want you to throw out. Seriously, don't even give it to charity. You won't be helping anyone.

Sheldon: Just the latest copy of Applied Particle Physics Quarterly.
Penny: Oh, you know, that is so weird that yours came and mine didn't.

Leonard: You are not Isaac Newton.
Sheldon: No, no, that's true. Gravity would have been apparent to me without the apple.