Leonard: If I take it off, Sheldon wins.
Penny: Sweetie, every night you don't kill him in his sleep, he wins.

Amy: Do you have any idea how hard it is to laugh at a knock knock joke that starts "Knock Knock Knock, Amy. Knock Knock Knock, Amy. Knock Knock Knock, Amy"?

Sheldon: Sheldon Cooper does not get lucky.
Amy: You and me both, brother.

Sheldon: No, that's okay. I can fight my own battles. Isn't that right, Bawwy?
Barry Kripke: Is that a reference to my speech impediment? That's pretty hurtful. I can't control it.
Sheldon: You're right. That was uncalled for. I take it back.
Barry Kripke: Of course you do, because you're The Retractor!

Leonard: You don't go into science for the money.
Bernadette: Speak for yourself. Last month my company both invented and cured restless eye syndrome. Ka-ching, ya blinky chumps!

Penny: Thank you, I needed to hear that. Why can't Leonard understand it?
Sheldon: Because he's not like us, Penny. We're dreamers!
Penny: Yeah, I need to start cracking the window when I leave you in the car.

Amy: As my mom used to say, "When you're doing a puzzle, it's like you've got a thousand friends." She was full of fun lies like that.

Penny: If you guys were hungry, why didn't you order something at the restaurant?
Bernadette: We did. You never brought it.
Penny: Oh, that's right. Nachos and a turkey club.
Amy: Not even close.
Penny: Well, I was too busy standing up for my friend to worry about your ... I want to say salmon.
Amy: You want to say sorry.

Sheldon: I know why. You've come to me because you're my Obi-Wan.
Arthur: I'm not familiar with that. Is that an Internet?

Amy: I guess it must have been back when I was in the Girl Sprouts.
Bernadette: Girl Sprouts?
Amy: My mom made it up as an alternative to the Girl Scouts. She didn't want me selling cookies on some street corner like a whore.

Raj: It's too late. He's been murdered by someone in this room. Welcome to another classic Koothrappali murder mystery dinner.
Amy: I'm leaving.

Penny: Sheldon, what did we say about being a nicer friend?
Leonard: Thank you.
Penny: Leonard, what did we say about being a gullible weeny?

Penny: [on the phone] No, mom. It's the same guy I've been going out with for the past two years. Yeah, the scientist. Well, it's complicated. He works with lasers and atomic magnets. No, I did not see it coming. No, we have not set a date. No, I am not pregnant. Yeah, this is a first for our family.

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.

Bernadette: Aww, Raj did the dishes.
Howard: How do you know I didn't do them?
Bernadette: Because once when all the knives were dirty, you cut a bagel with your keys.