Leonard: See, this is the good thing about having a girlfriend 9,000 miles away I can spend my nights doing whatever I want.
Howard: You mean playing nerd games with us and then taking a suspiciously long shower?
Leonard: Maybe.

[Sheldon karate chops Leonard in the shoulder]
Leonard: Ow! Why did you do that?
Sheldon: To send a message: she's not for you!
Leonard: What?
Sheldon: Not for you!

Let me know when you're done canoodling! Mommy needs a foot rub!

Mrs. Wolowitz

Amy: If it makes you feel any better, the only person who signed my yearbook was my mother.
Leonard: Aww.
Amy: "Dear, Amy. Self-respect and a hymen are better than friends and fun. Love, Mom."

Howard: Can you believe grown men sit around and play with toy trains?
Bernadette: That's pretty big talk for a man with a closet full of magic tricks at his mother's house.

Amy: Should I go? I've been told, sometimes, I overstay my welcome.
Leonard: Wha ... who told you that?
Amy: Well, most recently my gynecologist.

Howard: This may be hard for you to hear, but when I say "honey," I mean my fiancee.
Raj [whispers into Howard's ear]
Howard: Yeah, well, now it means her.

The tinier the train the more concentrated the fun.

Sheldon

Bernadette: I'm not going to live with your mother. Not now. Not ever.
Howard: Somebody, obviously, has some mommy issues.

I've seen pictures of your mother. Keep eating.

Sheldon [to Penny]

Leonard: You're my woman. I'm going to make you feel things you have never felt before.
Priya: Leonard
Leonard: That's right, say my name and beg me for more because I'm going to give it to you.
Priya: My parents are here.
Priya's father: Hello, Leonard, if I may also say your name.

Sheldon: Name your price.
Amy: Kiss me where I've never been kissed before.
Sheldon: You mean like Salt Lake City?
Amy: Nevermind.

The Big Bang Theory Season 5 Quotes

You can't blame yourself. When your prefrontal cortex fails to make you happy promiscuity rewards you with the needed flood of dopamine. We, neurobiologists, refer to this as the skank reflex.

Amy

I feel like two totally different people. Dr. Jekyyl and Mrs. Whore.

Penny