Sheldon: Penny.
Penny: Yeah.
Sheldon: Thanks for letting me stay here.
Penny: Oh, you're welcome sweetie.
Sheldon: Okay, I'm sleepy now get out.

Sheldon: What exactly does that expression mean, 'friends with benefits?' Does he provide her with health insurance?

Sheldon: You know, I'm given to understand that there's an entire city in Nevada devoted specifically to help people like Howard forget their problems. They replace them with new problems such as alcoholism, gambling addiction and sexually transmitted diseases.

Leonard: What were you doing at Penny's?
Sheldon: Well, we had dinner, played some games, and then I spent the night. Oh, and you'll be happy to know that I now have a much better understanding of 'friends with benefits.'

Sheldon: How often does one see a beloved fictional character come to life?
Wolowitz: Every year at ComiCon. Every day at Disneyland. You can hire Snow White to come to your house. Of course they prefer if you have a kid.

Sheldon: Do those sound like castanets to you?
Leonard: The box says 'kitchen'.
Sheldon: So? Do cocaine smugglers write 'cocaine' on the box?

Sheldon: Listen to that! 'Stomp, stomp, stomp.' It's Wolowitz and his stacked heels that fool no one.

Sheldon: She calls me moon-pie because I'm nummy-nummy and she could just eat me up.

Sheldon: Everything is better with Bluetooth.

Sheldon: I'm sorry, coffee's out of the question. When I moved to California I promised my mother that I wouldn't start doing drugs.

Sheldon: You are effectively paying yourself five dollars and nineteen cents a day.
Penny: A day?
Sheldon: There are children working in sneaker factories in Indonesia who out-earn you.

Sheldon: Penny, I'm a physicist. I have a working knowledge of the entire universe and everything it contains.
Penny: Who's Radiohead?
Sheldon: I have a working knowledge of the important things in the universe.

Sheldon: What rat have you recruited to the SS sinking ship?
Leslie: Hello Sheldon.
Sheldon: Leslie Winkle.
Leslie: Yeah Leslie Winkle. The answer to the question, who made Sheldon Cooper cry like a little girl?
Sheldon: Yes well I am polymerised tree saps and you are an inorganic adhesive so whatever verbal projectile you launch in my direction is reflected off me, returns on its original trajectory and adheres to you.
Leslie: Oh, ouch.

Sheldon: If I'm permitted to speak again, Dr. Sheldon Cooper for the win!

Sheldon: Yeah, I'm definitely going with colonoscopy.
Leonard: Okay, bye. (Off the phone) My mother's coming for a visit.
Howard: How about that, you were right.