Penny: Oh, no, I can't give up my acting classes. I'm a professional actress.
Leonard: You've had an acting job where you got paid?
Penny: That is not the definition of professional.
Leonard: Actually, it kind of - let's keep looking.

Sheldon: I remember the song! It's called "Darlin'" by the Beach Boys! Oh, thank goodness! I'm not crazy! I don't have to take a pigeon as my bride!
Leonard: There goes our shot at him living on the roof.

Sheldon: This song is never going to stop. Have you ever dealt with something so relentlessly irritating?
Leonard: That's a trick question, right?

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: OK, is everyone clear on the plan?
Howard: Yes, Koothrappali's going to wet himself, I'm gonna throw up, Sheldon's gonna run away and you're going to die. Shall we synchronize our watches?

Sheldon: There once was a brave lad named Leonard.
With a fi fi fiddle dee dee.
He faced a fearsome giant.
While Raj just wanted to pee.

Leonard: Sheldon, would you be prepared on a non-presidential basis, to create an emergency ad-hoc slurpee/icee equivalency?
Sheldon: Oh Leonard, you know I can't do that.