Leonard: I gave it a lot of thought and I decided it was time for us to live together.
Howard: Leonard, huge mistake. There's a whole buffet of women out there and you're just standing in the corner eating the same devilled egg over and over again.

Stephanie: I just performed a Sheldonectomy.
Leonard: Careful, if you don't get it all, it'll only come back worse.

Sheldon: I must say, Howard, I think a detailed letter to MIT describing your current circumstances might entitle you to a refund on your master's degree.

Sheldon: All right, what if we use this two-inch PVC to reinforce the center cross-support?
Howard: No good. I mean, it might work for the Japanese and the Americans, but have you seen the size of the Russians they've got up there? The thing has to hold up against a hearty potato-based diet.

Raj: Of course you feel terrible. You completely screwed up your karma, dude.
Sheldon: You don't really believe in that superstition, do you?
Raj: It's not superstition. It's practically Newtonian. For every action, there's an equal and opposite reaction. Leonard pretends to be a friend and acts like a two-faced bitch. Therefore, he is reborn as a banana slug. It's actually a very elegant system. You know, what goes around comes around.

Howard: Guys, we have a code red.
Sheldon: Do you mean code red for the hospital emergency alert, code red the computer worm, or Code Red the cherry-flavored soft drink from the makers of Mountain Dew?

Leonard: It must be hell inside your head.
Sheldon: At times.

Leonard: Just think. Thanks to your hard work, an international crew of astronauts will boldly go where no man has gone before.

Howard: Is that supposed to be funny?
Sheldon: I believe it is. The combination of the Star Trek reference and the play on words involving the double-meaning of the verb to go suggests that Leonard is humorously mocking your efforts in space plumbing.

Penny: Well, does it bother you, me going out with one of your friends? 'cause you know, you and me.
Leonard: No, no that's the past. I'm really more of a right now kind of guy. You know, living in the moment. Although I do have to live a little in the future, 'case, well, that's my job. Of course, my fondness for classic science fiction does draw my attention backwards, but those stories often take place in the future. In conclusion, no, it doesn't bother me.

Howard: Ugh. This mu-shu pork is burning a hole through me duodenum.
Raj: Leviticus 11:3 "Only that which parteth the hoof and cheweth the cud among the beasts shall ye at."
Howard: Hey, do I mock you with the Bhagavad-Gita every time you scarf down a whopper?

Leonard: Look, you do understand that Sheldon really doesn't care when he gets the money back. It's actually one of the few idiosyncrasies that doesn't make you want to, you know, kill him.

Penny: I've been having leftovers at the restaurant for like four days and I wanted something different. So sue me.
Sheldon: Forgive me, Penny, but that would be the very definition of a frivolous lawsuit.

Leonard: Here you go. Oh, you owe me another two dollars. The price of mu-shu pork went up.
Howard: It's getting tougher and tougher to be a bad Jew.

Penny: Well, remember Kurt?
Leonard: Your ex-boyfriend?
Penny: Yeah. He got arrested for taking a whiz on a cop car.
Leonard: What?
Penny: He was drunk.
Leonard: I would hope so.