Leonard: Hang on, uh, uh, roommate agreement. Ha! Um, no hootenannies, sing-a-longs, or barbershop quartets after 10:00 p.m.

Leonard: Penny, as a scientist, my job is to figure out why things happen. But I don't think I'll ever understand how someone like me could get to be with someone like you. You know maybe I don't need to understand it, I just need to be grateful. I love you, Penny.

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.

Sheldon: Gotta run. (Looks down at scissors) But not with scissors, that would be unsafe.

Sheldon: Bongo solo!

Leonard: It's 3 in the morning!
Sheldon: 3 in the morning is a good time for bongos.
Leonard: I was sleeping!
Sheldon: Leonard sleep while I play bongos.
Leonard: No, I don't.
Sheldon: Leonard no sleep while I play bongos.