Penny: So, how've you been?
Sheldon: Well, my existence is a continuum, so I've been what I am at each point in the implied time period.

Sheldon: I'm sorry. There there. Everything's gonna be okay. Sheldon's here.

Sheldon: Pee for Houston, pee for Austin.
Pee for the state my heart got lost in.
And shake twice for Texas.

Leonard: What do you want?
Sheldon: You may wanna sit down.
Leonard: I'm in bed.
Sheldon: Point taken. You may wanna sit up.

Sheldon: While we live in a deterministic universe, you do have free will. Now sit down.

Wolowitz: You said you were going for a walk.
Sheldon: I didn't say outside.

Sheldon: Well then, as my meemaw would say, looks like we butchered a pig but nobody wanted bacon.

Sheldon: Go Team Leonard!

Sheldon: Bring out the Red Bull, it's time to rock Mario old school!

*Penny enters the apartment without knocking*
Sheldon: Who is it? Hello, Penny. It's open, come in. Sarcasm.

Sheldon: Please. We're facing a far more serious problem than stray arachnids.
Leonard: It's not so bad.
Sheldon: Not bad? It's horrible. You hear stories about this things, but you never think it'll happen to you.
Leonard:So they steamed your dumplings. Get over it.

Sheldon: We have a bowl. Our keys are in the bowl. You should get a bowl.
Penny: I just don't understand; how can beautiful mind of Sheldon Cooper forget his keys in the first place?
Sheldon: I left them in the bowl.

Sheldon: This is to train for a three month expedition to the magnetic North Pole.
Penny: What?!
Sheldon: I don't know how that sentence could possibly confuse you, but to elaborate, I'm going to the Arctic Circle with Leonard, Wolowitz and Koothrappali.

Sheldon: *After just being jailed, at the biggest guy in the cell who's sitting on a bench* That's my spot.

Sheldon: That's the toilet?
Policeman: Well, it ain't a wishin' well!
Sheldon: Please tell the judge I'm ready to apologize.