Sheldon: *knock knock knock* Dr. Wolcott? *knock knock knock* Dr. Wolcott? *knock knock knock* Dr. Wolcott? [sound of many locks clacking]
Howard: That's a lot of locks.
Leonard: Mm. That was a lot of knocks, they were made for each other.

Howard: I love watching Raj and Sheldon try to work together.
Leonard: Yeah, it's like if Alien and Predator decided to go partners in a Jamba Juice.

Penny: Sweetie, you know you're supposed to wear clothes under a graduation gown?
Leonard: A. Surprised you know that. B. I wanted to look like a sexy graduate for you.

Beverly Hofstadter: I read your paper. It was very impressive.
Sheldon: Oh, thank you.
Leonard: We just spent two hours in traffic. Did you think to mention to me that you liked our paper?
Beverly Hofstadter: Of course I did, but it's a mother's job to make sure her child's self-esteem is not dependent on anyone's approval.
Leonard: That's so sweet, you think I have self-esteem.

Sheldon: Can I at least kick down the door?
Leonard: You're welcome to try, but the other day, it took you 15 minutes to get into a FedEx box.

Leonard: On the count of three, both of you bounce the balls as hard as you can. The highest bounce wins the office.
Barry Kripke: Oh, you are going down, Cooper.
Sheldon: I don't think so, Kripke. I've bounced many a rubber ball in my day.
Leonard: All right, that's enough trash talk. One, two, three.

Penny: And now Ben Affleck is Batman?
Emily: Oh, he was great in Shakespeare in Love.
Penny: Ooh, we should watch that next girls' night.
Bernadette: We could do a double feature with the Leonardo DiCaprio Romeo + Juliet.
Penny: Oh, I love me some Leo.
Leonard: And it's gone.

Priya: It's a little weird your ex-girlfriend hanging out here all the time.
Leonard: I know. I usually never see my ex-girlfriends, unless their hard drives crash.

Penny: All right, this is making me crazy. Somebody's got to go over there.
Leonard: You got feet and legs, you do it.

Bernadette: You know, I just read that a team at MIT developed a device that helps people read human emotions.
Leonard: And you think we can get those guys to reprogram Sheldon? Cool.

Leonard: I got all your favorites. Beer, wings, sliders. We can watch the football game. I even painted my stomach.
Penny: Go Sports?
Leonard: Well, in case you were in the mood for baseball, I didn't want to look ridiculous.

Sheldon: I suppose you're wondering why I put you through all this.
Leonard: You mean the last two minutes or the last 20 years?

Penny: Oh, there it is again. You think I'm stupid.
Leonard: No, there's a difference between being stupid and acting stupid.
Penny: Oh, yeah? Well, there's a difference between being a jerk and being an ass.
Leonard: No, there isn't. They're synonyms.

Sheldon: Leonard, quick. I need you to get me to Arcadia within the hour. The train store's having a sale.
Leonard: Why can't Amy drive you?
Sheldon: Because of the tradition that I cannot see Amy on the day of the train store sale.
Leonard: Please, please see a doctor.

Sheldon: I don't come into your house and touch your board.
Leslie: There are no incorrect equations on my board.
Sheldon: Oh, that is so... so...
Leslie: I'm sorry, I've got to run. If you come up with an adjective, text me.