Leonard just realized that Penny's been hiding him from her friends because he's a tiny little man who flies kites

Raj

Wolowitz: Do you like role playing games?
Bernadette: Like in the bedroom or dungeons and dragons?
Wolowitz: Either?
Bernadette: No

Sheldon: I came here to defeat Wil Wheaton: the man who destroyed my dreams, but I can't destroy Wil Wheaton: the man who loved his mee-maw

Wolowitz: Listen, you have to come to Shabbas dinner at my house sometime.
Bernadette: Why?
Wolowitz: A Catholic girl like you, wearing big cross like that, might just give my mother that big brain aneurysm I've been hoping for.
Bernadette: Only if you come to Sunday dinner at my house wearing a yamaka
Wolowitz: It's a date

Bernadette: Does your mother call you every day at work to see if you've had a healthy lunch?
Wolowitz: My mother calls me every day to see if I've had a healthy bowel movement

Wil [about Sheldon]: Did that guy just say, "revenge is a dish best served cold" in Klingon?
Stuart: I believe so
Wil: What is wrong with him?
Stuart: Everyone has a different theory

Sorry boys, say "hi" to your mother when she comes to pick you up... or I could just tell her later tonight!

Raj

It might also interest you to know that Wil Wheaton currently ranks sixth on my all-time enemies list, right between director Joel Schumacher, who nearly destroyed the Batman movie franchise, and Billy Sparks, who lived down the street from me and put dog poop on the handles of my bicycle

Sheldon

Leonard: You know deep down on the inside, Howard's a good guy
Penny: The problem isn't what's on the inside, it's the creepy candy coating

Raj: Did you know, in the Mumbai-McDonald's you can't get a Big Mac? All you can get is a Chicken Maharajah Mac. And the special sauce: Curry. Which, in India, believe you me, is really not that special

Raj: No, no, no, no, that rate is much too low for what you'd expect from this collision. Do you understand we're taking about dark matter colliding in outer space?
Sheldon: Yes, of course I understand, and who are you to tell me about outer space?
Raj: Well, I am the astrophysicist! Astro means space!
Sheldon: Astro means star.
Raj: Okay, let me just tell you, if we were having this argument in my native language, I'd be kicking your butt!
Sheldon: English is your native language!

Okay, please don't take this the wrong way, but I'd rather swim butt-naked across the Ganges with a paper cut on my nipple and die a slow agonizing death from a viral infection than work with you

Raj [to Sheldon]

TBBT Quotes

Penny: Hey, Sheldon, did you change your Wi-Fi password again?
Sheldon: Yes, it's "Penny, get your own Wi-Fi." No spaces.

Sheldon: Why do you have the Chinese character for "soup" tattooed on your right buttock?
Penny: It's not "soup," it's "courage."
Sheldon: No it isn't. But I suppose it does take courage to demonstrate that kind of commitment to soup.
Penny: How'd you see it? You said you wouldn't look.
Sheldon: Sorry. As I told you, the hero always peeks.