Sheldon: *knock knock knock* Leonard? (x3)
Leonard: What, Sheldon!? What, Sheldon!? What, Sheldon!?
Sheldon: Tell me what you see here.
Leonard: The blunt instrument that will be the focus of my murder trial?

Penny: Here you go, (to Leonard) Quesadilla, (to Howard) Salad, (to Raj) Here's your pizza. And thanks to Sheldon's heated discussion with my manager, one barbecue bacon cheeseburger, barbecue sauce, bacon, and cheese on the side.
Sheldon: Thank you!
Penny: Go ahead. Eat it. I dare you!

Howard: Hey, you want to make sure he gets nowhere with Penny without jeopardizing your friendship with either of them?
Leonard: I'm listening.
Howard: Just tell him to do everything you've done with her for the last two years.

Sheldon: I wouldn't tell you the secret. Sssh!
Leonard: What secret? Tell me the secret.
Sheldon: Mom smokes in the car. Jesus is okay with it, but we can't tell dad.
Leonard: Not that secret, the other secret.
Sheldon: I'm Batman! Ssssh!

Wolowitz: I'm a horny engineer, Leonard. I never joke about math or sex.

(Sheldon smiles in a grotesque way).
Howard: Oh crap that's terrifying.

Leonard: Penny, you don't want to get into it with Sheldon. The guy's one lab accident away from being a super villain.

Wolowitz (watching America's Next Top Model): Oh, look! That's the future Mrs. Wolowitz. No, wait! That's the future Mrs. Wolowitz. With her head in the lap of... what a coincidence... it's the future Mrs. Wolowitz.
Leonard: Yeah, and they can all move in with you and your mother. The current Mrs. Wolowitz.

Leonard: What were you doing at Penny's?
Sheldon: Well, we had dinner, played some games, and then I spent the night. Oh, and you'll be happy to know that I now have a much better understanding of 'friends with benefits.'

Mrs. Wolowitz What's going on? Are you boys roughhousing?
Howard: We're just talking, ma.
Mrs. Wolowitz If you don't settle down right now, I'm not going to let you have any more sleepovers.

Raj: What do you say, Howard?
Howard: I say Vegas baby!
Raj: What are you gonna tell your mother?
Howard: Sea World baby!

Sheldon: I still don't see why I need a driver's license. Albert Einstein never had a driver's license.
Howard: Yeah, but Albert Einstein didn't make me wet myself at 40 miles an hour.
Penny: Yeah, and I never wanted to kick Albert Einstein in the nuts.

Mrs. Wolowitz Howard, there's a blonde girl, Patsy, here to see you.
Howard: Who?
Mrs. Wolowitz Okay, now she's saying it's Penny.

Hooker: What's your name?
Raj: Rajesh Ramayan Koothrappali.
Hooker: Hello Rajesh Ram...Hello Rajesh.

Sheldon: All I need is a healthy ovum and I can grow my own Leonard Nimoy.
Penny: Okay, all I'm giving you is the napkin, Sheldon.