Leonard: I think any university would want you -- except, of course, any university that had already had you, because they would have already wanted you, before they, you know, got you.
Sheldon: From the mind that brought you "hi-lo."

Dr. Cooper, thank goodness! I completely forgot your address, but then I remembered that I had written it on my hand. Lucky for me, I didn't confuse it with what I had written on my other hand, which were the coordinates for a newly-discovered neutron star, because if I tried to go there, I'd be crushed by hypergravity.

Dr. Plimpton

I have a lady friend who will be staying with me for a few days. I want her to feel at home; I also bought scented soaps, pantyhose, Midol, calcium chews, and what is apparently a yogurt specifically designed to regulate the female bowel.

Sheldon

Leonard: Are you planning on kidnapping a woman?
Sheldon: Sarcasm?
Leonard: Yes, but mixed with a little bit of concern.

Don't let Goofy near him. He'll have nightmares, and I'll have to deal with it

Leonard

And now, as promised, the tangent. Sheldon and the Hell-hound. Or. How I Lost My Hot Dogs.

Sheldon

Raj: Do you think you'll go to hell for eating sweet and sour pork?
Wolowitz: Jews don't have Hell. We have acid reflux.

Does the elastic woman in "The Incredibles" use birth control or can she actually be a diaphragm.

Raj

Allegiance to male comrades before women who sell their bodies for money.

Sheldon

Sometimes your lack of social skills astonishes me.

Sheldon

It was a lot of work to accommodate you in my life. I'd hate to think that effort to be in vain.

Sheldon

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.

TBBT Quotes

Given that St. Valentine was a 3rd century Roman priest who was stoned and beheaded, wouldn't a more appropriate celebration of the evening be taking one's steady gal to witness a brutal murder?

Sheldon

Sheldon: Why are you crying?
Penny: Because I'm stupid!
Sheldon: Well that's no reason to cry; one cries because one is sad. For example, I cry because others are stupid and it makes me sad.