Leonard: But we all agreed the third Thursday of every month will be "Anything Can Happen Thursday"
Sheldon: Apparently the news didn't reach my digestive system, which when startled has it's own version of "Anything Can Happen Thursday"

Sheldon [looking for musical instrument in new neighbor's boxes]: Do those sound like castanets to you?
Leonard: The box says "kitchen."
Sheldon: So? Do cocaine smugglers write "cocaine" on the box?

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

Howard: you know what would bea great idea? We get some girls over here and we play laser obstacle strip chess
Leonard: Believe me howard, any girl who would want to play that, you don't want to see naked
Howard: You underestimate me

Leonard: Well, it seems once again you're caught between a rock and a crazy place.
Sheldon: Oh, I hate when that happens.

Leonard: You know what baffles me Sheldon?
Sheldon: Based on your academic record, I could guess any number of things

Penny: What are we gonna do?
Leonard: We? No, no, no. You had your chance to be "we" for like a year and a half now. Right now, you are you and you are screwed.

Leonard [about his mother]: She's only been here a day and a half, and I'm seriously considering alcoholism as a new career path.
Penny: Hey, I talked to her for five minutes yesterday, and I've been half bombed ever since.

Penny [about his mom]: You can't let her get into your head
Leonard: It's too late for me, my head is her summer house

Mrs. Hofstadter [about Penny]: If you want to have sex with that woman, find out what kind of cologne her father wore
Leonard: Hello mother

Leonard: Okay, is everyone clear on the plan?
Wolowitz: Yes. Koothrappali is going to wet himself, I'm going to throw up, Sheldon is going to run away, and you're going to die. Shall we synchronize our watches?

Leonard: What was the plan?
Penny: Um, waitress for six months and then become a movie star.
Leonard: Was there a Plan B?
Penny: TV star.

TBBT Quotes

Mrs. Cooper: Shelly! I'm so glad you're here!
Sheldon: I saw you having naked sex.

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.