Penny: Can you please go talk to him?
Leonard: Come on, I take care of him all day long. You do it for once.
Penny: Once? Who got the gum out of his hair?
Leonard: What do you want, a medal? It was your gum.

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: 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.

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

Penny: So you have a song stuck in your head. It happens to everybody.
Sheldon: Well, I'm not everybody. I have an eidetic memory. I should be able to remember what song this is, but I can't. Something's wrong with me.
Penny: I told you if we were patient, he'd figure it out for himself.

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

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.