Sheldon: I can't give a speech.
Wolowitz: No, you're mistaken. You give speeches all the time. What you can't do is shut up.
Raj: Before the movie, you did twenty minutes on why guacamole turns brown. It turned brown while you were talking.

Wolowitz: How's it feel to get beaten up by a girl?
Sheldon: It's not the first time. I have a twin sister whose assaults began in utero. If only I'd had the presence of mind to absorb her. Then I'd have a mole with hair in it, instead of a tedious yearly Christmas letter.

Penny: Who's Adam West?
Sheldon: Who's Adam West!? Leonard, what do you talk about after the coitus?
Wolowitz: My guess is "four minutes, a new record!"

How can I possibly discuss with Stan Lee the scientific foundations for inter-stellar flight on a silver surfboard when part of my brain will be scanning his face for signs of contagious skin disease?

I don't trust banks. I believe that when the robots rise up, ATM's will lead the charge.

Wolowitz: Why do you have all of these unopened paychecks in your desk?
Sheldon: Because most of the things I'm planning to buy haven't been invented yet.

Did he finally write a sequel to his autobiography? I'm sure ages 79 to 87 were just action packed.

Sheldon: I believe you know why I'm here.
Penny: I always figured it was to study us, discover our weaknesses, and report back to your alien overlords.

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: 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.

One bacon cheeseburger, breaking two Jewish dietary restrictions simultaneously.

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?

TBBT Quotes

Penny: Here's a question-- as an alien pretending to be human, are you planning to engage in any post-prom mating rituals with Amy?
Sheldon: There are post-prom mating rituals?
Penny: Not always. Unless your date drives a van with an air mattress, then always.
Sheldon: Well, if it's part of the prom experience, then I'm open to it.
Penny: You're kidding.
Sheldon: I may be an alien, but I have urges.If Amy wants to copulate by firing her eggs into space, well, then, I will happily catch them with the reproductive sac on my upper flermin. I'm not the best at reading facial cues, but I can see that you're a little turned on.

Penny, there's only one cookie with something in the middle that solves life's problems, and that's an Oreo. Or a Nutter Butter, if you're in a pinch.

Sheldon