Instead of underpants, I covered my crotch with potato salad this morning. Thoughts?

Leonard

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: Do you recognize this?
Leonard: Not the roommate agreement!
Sheldon: Indeed, the roommate agreement. I call your attention to the friendship rider in Appendix C: Future Commitments, Number 37. In the event one friend is ever invited to visit the Large Haldron Collider, now under construction in Switzerland, he shall invite the other friend to accompany him.
Leonard: For god's sake!
Penny: You actually put that in an agreement?
Leonard: We also put in what happens if one of us gets a MacArthur grant, or if one of us gets super powers, or if one of us turns into a zombie.
Sheldon: He can't kill me, even if I turned.
Penny: Ts there anything in there if one of you gets a girlfriend?
Sheldon: No, that seemed a little far fetched.

Penny: We're going to Disneyland and ride the Matterhorn?
Leonard: How does that involve air travel?
Penny: We're going to Disney World and ride the Matterhorn?

Leonard: This tray contains clues as to what you and I are going to be doing on Valentine's Day.
Penny: Wow okay, let's see. We got milk chocolate, Swiss cheese, fondue... my lactose intolerant boyfriend is going to eat all this and I'm going to climb on your back and rocket to the moon?

One bacon cheeseburger, breaking two Jewish dietary restrictions simultaneously.

Sheldon

Sheldon: Your cell phone was off.
Leonard: Because we didn't want to be disturbed!
Sheldon: Well that didn't work out, now did it?

I'm a walking, brown Yelp.com.

Raj

Penny, I told you if you don't put him in his crate at night, he just runs around the apartment.

Leonard

Sheldon: I asked myself what is the most mind-numbing, pedestrian job conceivable and three answers came to mind: a toll booth employees, an Apple store genius, and what penny does. Because I don't like touch other peoples' coins and I refuse to contribute to the devaluation of the word genius, here I am.

I haven't seen him this stuck since he tried to figure out the third Matrix movie.

Leonard

Wolowitz [about Sheldon]: How long's he been stuck?
Leonard: Intellectually about 30 hours, emotionally about 29 years.
Wolowitz: Have you tried rebooting him?
Leonard: No, I think it's a firmware problem.

The Big Bang Theory Season 3 Quotes

Wolowitz: Sheldon. You remember the first few weeks; we were looking for magnetic monopoles and not finding anything, and you were acting like an obnoxious, giant dictator?
Raj: I thought we were going to be gentle with him.
Wolowitz: That's why I added the "tator"

Wolowitz [after seeing Penny jump Leonard]: Damnit, I should have gone over and said we were back
Raj: Yeah, it was "first come, first serve."