Sheldon: Yes, instead of going out, they just stay home and have constant coitus.
Leonard: Well, I didn't want to say it, but I-I do like to hear 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: 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?

Sheldon: Oh, Stuart, good. I was wondering, will you be accepting Bitcoin?
Stuart: Well, I don't know what that is, but it's got "coin" in it, and my cash register doesn't, so yeah.

Mrs. Wolowitz: Howard, what's going on?! Are you boys roughhousing?!
Howard: No, we're not roughhousing! We're scientists! Scientists don't roughhouse!
Mrs. Wolowitz: Excuse me, Mr. Grown-up!

Mrs. Wolowitz: Howard, I made cookies for you and your little friends!
Howard: They're not my little friends, and we don't want cookies!
Leonard: Actually, a cookie sounds good.
Howard: All right, we'll have cookies! Thank you very much!