Rajesh: Excuse me but I don't think Penny is out of line at all. You don't own her. It's like my girl Beyonce says: If you like it you should've put a ring on it.

Leonard:What am I supposed to say? Sure, Penny, I'm cool with having your old boyfriend sleep in your apartment.
Leonard imitating Penny: Well, Leonard, it doesn't matter if you're cool or not, 'cause I'm penny and I'm pretty and I can do whatever the hell I want.

Sheldon: Where exactly does the half-sandwich come from? Are you giving me half of someone else's sandwich, or do I have to wait for someone in the restaurant to order the other half?

Wolowitz: Do you think I'd have rather been with you or sitting around for hours listening to my mother saying "Have y'ever pee'd so much in your life?"
Rajesh: Oh, you are such a momma's boy.
Wolowitz: Don't bring my mother into this.
Rajesh: You brought your mother into this!

Penny: Wow, Sheldon, I cannot believe you made up your own game.
Sheldon: Oh, Research Lab is more than just a game. It's like the slogan says, the physics is theoretical, but the fun is real.

Penny: How is that not talking to me like I'm an idiot? It's my friend, it's my couch, and it's my freakin' life!
Sheldon: It's also your roll.

Sheldon: Come on, Leonard, if you roll a six, Penny dies horribly in a nuclear meltdown. See what I mean when I say the fun is real?

Leonard: So, by friend, do you mean friend friend, gay friend, or ex boyfriend who you're now platonic with but still might have a thing for your friend?
Penny: Well, he's definitely not gay.
Leonard: Oh, a definitely not gay musician sleeping on my girlfriend's couch. Yippee!

Penny: Oh and FYI, you never even heard of The Black Eyed Peas until you met me.
Leonard: I'd heard of them. Didn't know they were a band.

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.

Stuart: I was thinking of closing early and going home, but let's face it, that's just a slightly smaller lonely room filled with comics.

Leonard: Well, I can't read your mind, Penny!
Penny: Really? Why not? You're so smart, and I'm so dumb.

Raj: I don't care! And why don't you think I can find a woman for myself?
Mrs. Koothrappali: Because you're twenty-seven, and the closest thing we have to a daughter-in-law is that Jewish boy Howard.

Penny: All right, five. One, two, three, four, five. Oh, wow, look at that, my Department of Defense research grant is renewed.
Sheldon: Oh! Great roll! Now you can demolish your Soviet-style cyclotron and build the large Hadron Collider.
Penny: Yay.

Sheldon: Hey, I thought of a game we can play in the car.
Leonard: I don't want to play a game, Sheldon.
Sheldon: It's called Scientists. Now, I will name three scientists, then you will put them in order of the size of their contribution to their respective fields. To make this game even more compelling, you must consider only the contribution of the man to the field, not the validity of the field itself. For example, Abu Musa Jabir ibn Hayn made a greater contribution to the discredited field of alchemy than Halbert Vanderplatt made to neurobiology. Okay, ready to have some fun?