Sheldon: For the record, I do have genitals. They're functional and aesthetically pleasing.

Leonard: What are we going to do?
Sheldon: Perform the experiment immediately.
Leonard: I'd love to, but we need liquid helium and our shipment's on back order for a month.
Sheldon: A month? What? Are you kidding me? That would have been a good time for you to soften the blow.
Leonard: That shirt brings out the blue in your eyes.
Sheldon: Thank you. Aren't you sweet?

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!

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.

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

Sheldon: Leonard, you may be right. It appears that Penny secretly wants you in her life in a very intimate and carnal fashion.
Leonard: You really think so?
Sheldon: Of course not. Even in my sleep-deprived state, I've managed to pull off another one of my classic pranks. Bazinga!

Sheldon: A neutron walks into a bar and asks how much for a drink. The bartender replies "for you, no charge".

Sheldon: Cause of Injury: Lack of Adhesive Ducks.

Sheldon: Well, well, well, if it isn't Wil Wheaton. The Green Goblin to my Spider-Man, the Pope Paul V to my Galileo, the Internet Explorer to my Firefox!

Sheldon: So, just to clarify, when you say three, do we stand up or do we pee?

Sheldon: What computer do you have? And please don't say a white one.

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

Penny: Why are there tears?
Leonard: Everything's fine. We just started talking about living arrangements.
Amy: Are you crazy? You know he's a flight risk!
Sheldon: That's exactly what I told him.

Leonard: I'm just saying, you catch more flies with honey than with vinegar.
Sheldon: You catch even more with manure, what's your point?

Sheldon: I believe I would like to alter the paradigm of our relationship.
Amy: I'm listening.
Sheldon: With the understanding that nothing changes what so ever - physical or otherwise, I would not object to us no longer characterizing you as not my girlfriend.
Amy: Interesting, now try it without the quadruple negative.