It might also interest you to know that Wil Wheaton currently ranks sixth on my all-time enemies list, right between director Joel Schumacher, who nearly destroyed the Batman movie franchise, and Billy Sparks, who lived down the street from me and put dog poop on the handles of my bicycle

Raj: No, no, no, no, that rate is much too low for what you'd expect from this collision. Do you understand we're taking about dark matter colliding in outer space?
Sheldon: Yes, of course I understand, and who are you to tell me about outer space?
Raj: Well, I am the astrophysicist! Astro means space!
Sheldon: Astro means star.
Raj: Okay, let me just tell you, if we were having this argument in my native language, I'd be kicking your butt!
Sheldon: English is your native language!

Sheldon: Yes, since their relationship became carnal, Penny has updated his designated term of endearment, distinguishing him from those she calls "sweetie," usually as an attempt to soften a thinly-veiled insult.
Penny: You're boring people, sweetie.
Sheldon: Although sometimes, she omits the veil entirely.

Leonard: I've always been a little confused abut this -- why don't Hindus eat beef?
Raj: We believe cows are gods.
Sheldon: Not technically. In Hinduism cattle are thought to be like gods.
Raj: Do not tell me about my own culture Sheldon! In the mood I'm in I'll take you out, I swear to cow!

Interesting. Sex works even better than chocolate to modify behavior. I wonder if anyone else has stumbled onto that

Sheldon: Leonard, you can't train my girlfriend like a lab rat
Leonard: Actually, it turns out I can
Sheldon: Well you shouldn't

Penny: I give up, he's impossible
Sheldon: I can't be impossible, I exist. I believe what you meant to say is, "I give up, he's improbable."

Penny: I'll tell you what, next french toast day, I'll make you oatmeal
Sheldon: Good lord, are you still gonna be here next french toast day?

Raj: I don't like bugs, okay? They freak me out.
Sheldon: Interesting. You're afraid of insects and women. Ladybugs must render you catatonic.

Raj: What happened?
Sheldon: Obviously another carnal fiasco with the 'Shiksee' goddess.
Howard: Shiksa. Shik-Sa.
Sheldon: Forgive me. Yiddish was not spoken in East Texas. And if it was, it wasn't spoken for long.

Howard, you know me to be a very smart man. Don't you think that if I were wrong, I'd know it?

Penny: You know, I do understand what you're going through.
Sheldon: Really? Did you just have the Nobel Prize in Waitressing stolen from you?

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.