*Leonard is kissing Penny, and Penny's dad enters*
Penny: Come on, honey, not in front of my dad.
Penny's dad: Relax, I've seen her do a lot worse with a lot stupider.

Penny: Okay, help me out here. How does an archaeology professor get that good with a whip?
Howard: Maybe he took a class at the adult bookstore. That's how I learned.

Sheldon:He'll be back.
Leonard: (Through the door) Of course, I'll be back, I live here!

Sheldon: You know, in difficult moments like this, I often turn to a force greater than myself.
Amy: Religion?
Sheldon: Star Trek.

Penny: Mrs. Cooper? Hey, it's Penny. I think I broke your son. Hold on. Talk to your mother.
Sheldon: (Crying) Mommy, I love you. Don't let Spock take me to the future!

Priya: What happened?
Bernadette: Howard's mother had a heart attack because I have sex with him and she can't.

Raj: When Winnie-the-Pooh got his head stuck in the honey tree, his friends all grabbed onto him and pulled and pulled.
Leonard: You do what you want, I'm not touching another man's honey tree.

Wolowitz: But you love that spot.
Sheldon: No, I love my mother. My feelings for my spot are much greater.

Wolowitz: Winnie-the-Pooh is out of the honey tree.

Sheldon: I'd like you to meet Oppenheimer, Frisch, Panofsky, Feynman, Weisskopf.
Mary: Yeah, I get it. You got a lot of cats, and you gave 'em cute Jewish names.

Priya: Indian parents are very protective of their children.
Howard: Right. Whereas Jewish mothers take a casual la-di-da approach to their sons.

Amy's Mom: It's nice to meet you too Sheldon, I honestly didn't believe Amy when she told me she had a boyfriend.
Sheldon: I assure you, I am quite real and I'm having regular intercourse with your daughter.
Amy's Mom: What?
Sheldon: Oh yes, We're like wild animals in heat. It's a wonder neither of us has been hurt!
Amy's Mom: Amy? What is he saying?
Amy: You wanted me to have a boyfriend, mother, well here he is! Have to sign off now. My hunger for Sheldon is stirring in my loins.
Sheldon: Oh yes. It's time for me to make love to your daughter's vagina.

Mrs. Wolowitz: Who's there? Are you a sex criminal?
Howard: Sex criminals don't have key, ma!
Mrs. Wolowitz: Where were you so late?
Howard: I was out with Bernadette
Mrs. Wolowitz: I know what that means, I watch Dr. Phil. I hope to God you used a condom.
Howard: I am not having this conversation with you, ma.
Mrs. Wolowitz: God forbid you get one of them fancy sex diseases.
Howard: Nobody has a disease!
Mrs. Wolowitz:I hope not. I share a toilet with you. Is that what you want, to give your mother herpes?

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.

Leonard: I'm the king of foreplay.