Leonard: I can do that. From now on, this mouth, you and food. That's it.

Leonard: What would you be if you were attached to another object by an inclined plane, wrapped helically around an axis?
Sheldon: Screwed?
Leonard: There you go.

Leonard: My point is, while you're spending all this time on your own, building computers or practicing your cello, what you're really doing is becoming interesting. When people finally do notice you, they're gonna find someone a lot cooler than they thought. And for those of you that were popular in high school, it's over, sorry. Thank you. Congratulations.

Leonard: [to a "smiling" Sheldon] We're here to see Koothrappali, not kill Batman.

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

Sheldon: Amy's mad at me, and I'm not clear why.
Penny: Okay, were you talking before she got upset?
Sheldon: Yes.
Penny: That's probably it.

Penny: Wait, what is wrong with you two? He was talking about television during their date night.
Sheldon: Oh, not just date night. Our 5th anniversary.
Penny: Okay, see, that's even dumber than you wondering if being bitten by a goat would give you the powers of a goat.
Sheldon: If that happens, don't make me wait ten years to watch you eat a tin can.