Penny: I hear you broke up with Amy.
Sheldon: Breakup would imply she was my girlfriend. She was a girl who was my friend who is now not my friend.
Penny: Wow, It's like the worst country song ever.

Penny: God, he's an ass when he drinks.
Wolowitz: He's an ass he doesn't. You just don't hear it.

I just run till I'm hungry, and then I stop for a bear claw.

Leonard: Penny, Steve Wozniack was one of the co-founders of Apple computer. He and Steve Jobs...
Penny: Yeah. I know who he is. I watch Dancing With the Stars.

Penny: Honey, have you ever run before?
Sheldon: Certainly. I've run from bullies, dogs, angry chickens and one particularly persistent PE teacher determined to bend me over and give me a scoliosis test.

Penny: Can I ask you a question?
Sheldon: Given your community college education, I encourage you to ask as many as possible.

Penny: OK. Well, then, there's a couple of things you should probably know.
Sheldon: I have a master's degree and two doctorates. The things I should know, I do know.

Penny: You have nice hair.
Amy: Are you a homosexual?
Penny: No!
Amy: Would have been more flattered if you were a homosexual.

Sheldon: As a native Texan, I must say that I've never heard the phrase "yee haw" used in quite that context.
Penny: Oh God.
Sheldon: "Oh God." That I've heard on multiple occasions.

Sheldon: This is for you
Penny: Ice cream?
Sheldon: I've been familiarizing myself with female emotional crises by studying the comic strip, "Cathy." when she's upset she says, "ack" and eats ice cream.
Penny: Ack.
Sheldon: If you were a cat, I would have brought you lasagna.

Leonard: If my PE teachers told me this is what I was training for I would have tried a lot harder.
Penny: Do or do not, there is no try.
Leonard: Did you just quote Star Wars?
Penny: I believe I quoted Empire Strikes Back.
Leonard: Oh my God. I'm lying in bed with a beautiful woman who can quote Yoda.

Penny: So what do you say, Sheldon, are we your X-Men?
Sheldon: No, the X-Men were named for the "X" in "Charles Xavier." Since I am Sheldon Cooper, you will be my "C-Men."

TBBT Quotes

It's very simple. Scissors cuts paper, paper covers rock, rock crushes lizard, lizard poisons Spock, Spock smashes scissors, scissors decapitates lizard, lizard eats paper, paper disproves Spock, Spock vaporizes rock, and, as it always has, rock crushes scissors

Sheldon

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.