Sheldon: Mom was right, hell is real.

Leonard: Howard, relax. I am not interested in your girlfriend.
Howard: I hope not. Because you don't wanna mess with me. *Gets in Leonard's face* I'm crazy.

Howard: Hope you don't mind, I told my girlfriend, Bernadette, she can join us for dinner.
Leonard: Sure, the more the merrier.
Sheldon: Wait, no. That's a false equivalency. More does not equal merry. If there was 2000 people in this apartment right now, would we be celebrating? No, we'd be suffocating.

Penny: Look, can we just forget about this extra stuff and can you just tell me what Leonard does?
Sheldon: Alright. Leonard is attempting to learn why subatomic particles move the way they do.
Penny: Really? That's it? Well, that doesn't sound so complicated.
Sheldon: It's not. That's why Leonard does it.

Howard: Bernadette say fo'shizzle to my nerdizzles.

Leonard: (to Penny) It upsets Sheldon when you play with the Sheldon.

Howard: Wazzup, my nerdizzles?

Sheldon: No, fig newtons are named after the town in Massachusetts, not the scientist. Hey, don't write that down.

Raj: Ha-ha! Eat my dust, racially stereotypical plumber.
Sheldon: That's not fair! I got stuck behind a tree.
Raj: And a cow, and a penguin. Face it dude, whether it's a real car or a virtual car, you can't drive.
Sheldon: Just need a little more practice.
Raj: What you need is cheat codes, motor skills and a genie who grants wishes to little boys who sucks at MarioKart.

Sheldon: Have you suffered a recent blow to the head?
Penny: Hey, you don't have to be so mean.
Sheldon: Oh, I'm sorry, (smiling) have you suffered a recent blow to the head?

Sheldon: Koko learned to understands over 2000 words, not one of which had anything to do with shoes.

Bernadette: This isn't a nonfat yogurt, this is fatty-fat-fat!

Howard: It's not enough you get the prom queen, you have to get the head of the decorating committee, too?

Howard: Just giving the lady the old tour of the salt mines.
Bernadette: (Giggling) He doesn't mean salt mines , he means where he works.

Penny: I have to go to the bathroom.
Sheldon: Can't you hold it?
Penny: Not for 2600 years!