Leonard: I have asthma. Back off!

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.

Amy: As my mom used to say, "When you're doing a puzzle, it's like you've got a thousand friends." She was full of fun lies like that.

Penny: [to Raj] Run to India.

Bernadette: (Shouting at another driver) Your kid might be a honor student but you're a moron!