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.

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?

Oh man, did the KISS Army repeal "Don't Ask, Don't Tell?"

Penny [after seeing Wolowitz in his goth outfit]

Leonard: Why would you buy peppermint schnapps?
Penny: Because I like peppermint, and it's fun to say schnapps!

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?

Leonard [about snuggie gift]: what does this mean?
Penny: Wine, credit cards and late night television are a bad combination

Penny [to comic book store owner]: What would you recommend as a gift for a 13 year old boy?
Stuart: A thirteen year old girl

Penny [at comic book store]: Everyone's staring at me!
Leonard: Don't worry, they're more scared of you than you are of them
Penny: Unlikely

Wolowitz: According to Alicia's Facebook page, she's hooking up with one of the producers on CSI.
Penny: Dead whore on TV, live one in real life.

Penny: It looks like the MySpace page of a 13 year old girl
Leonard: No it doesn't
Wolowitz: Oh please, Dateline could use it to attract predators

Sheldon: You'll effectively be paying yor self 5.19 per day
Penny: A day??
Sheldon: There are children in sneaker factories in Indonesia that outearn 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.

Leonard: Hi. I'm Leonard. You are beautiful. You pop, sparkle and buzz electric. I'm going to pick you up at eight, show you a night you will never forget.
Raj: Where are we going?