Penny: Wait, wait, she's not gonna come here looking for you, is she?
Leonard: Oh, relax. She took Sheldon to the hospital to get a brain scan.
Penny: Oh my God. What happened?
Leonard: Nothing. Mother likes looking at brains and Sheldon likes getting his brain scanned.
Penny: Geez, what a fun couple.

Sheldon: Woman, you are playing with forces beyond your ken.
Penny: Yeah, well your Ken can kiss my Barbie.

Raj: [to Amy] If you were having Sheldon's baby, would you really want him in the room?
Penny: Yeah, if he's in the room when they're making the baby, I'll give you $10.

Penny: I mean, who even reads Scientific American?
Leonard: It's kind of a big deal.
Penny: If it's such a big deal, how come the biggest celebrity they could get for the cover is a molecule?

Beverly Hofstadter: It might explain why the two of you have created an ersatz homosexual marriage to satisfy your need for intimacy.
Howard: Say what?

Leonard: She's only been here a day and a half, and I'm seriously considering alcoholism as a new career path.
Penny: Hey, I talked to her for five minutes yesterday, and I've been half bombed ever since.

Penny: I'm curious. What was Leonard like when he was little?
Beverly Hofstadter: I think you mean young. He's always been little.