Howard: Hey, you want to make sure he gets nowhere with Penny without jeopardizing your friendship with either of them?
Leonard: I'm listening.
Howard: Just tell him to do everything you've done with her for the last two years.

Howard: Okay make your little jokes, but out of the four of us, I'm the only one who's making real world contribution to science and technology.
Rajesh: He's right, this is an important achievement for two reasons. Number one and of course number two!

Sheldon: Why does Leonard get to go?
Wolowitz: Because he's upset over his situation with Penny, and if I have to hear about it again, I'm gonna kick him in his ovaries!
Leonard: Thanks for understanding.
Howard: I've got your back, sister!

Sheldon: For what it's worth, my mother says that when we deceive for personal gain, we make Jesus cry.

Howard: Ok, now, this is an exact duplicate of The Wolowitz Solid Waste Disposal System, as deployed on the International Space Station.
Raj: Don't you mean the Wolowitz Solid Waste Distribution System?

Sheldon: Yeah, I have to say I thought the toilet humor would get less funny with repetition. Apparently there is no law of diminishing comedic returns with space poop.

Leonard: Thanks for closed captioning my pain, Raj.

Sheldon: Have you notified NASA?
Howard: No. Are you crazy? What am I gonna say? I screwed up your toilet and pretty soon there's gonna be crap floating all over your nice shiny space station?

Sheldon: Hey, Stuart, have you read the new Flash?
Stuart: No.
Sheldon: Well I have and it will knock your socks off. Good luck getting them back on.

Howard: Here's an approximation of the spare parts available on the Space Station. We gotta find a way, using nothing but this, to reinforce this so the waste material avoids the spinning turbine.
Raj: You mean so it doesn't hit the fan?

Stuart: Here, Sheldon, I pulled the new Hellboy for you. It's mind-blowing.
Sheldon: Excuse me. Spoiler alert.
Stuart: I didn't spoil anything.
Sheldon: You told me it's mind-blowing.So, my mind is going into it pre-blown. And once a mind is pre-blown, it cannot be re-blown.
Stuart: I'm sorry.
Sheldon: Said the Grinch to Christmas.

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

Leonard: Hey, Stuart, I need to talk to you.
Stuart: Sure, what's up?
Leonard: I think I gave you bad advice about Penny, and I want to apologize.
Stuart: No, your advice was great.
Leonard: It was?
Stuart: Yeah, going slow really worked.
Leonard: You're kidding. Never worked for me.

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.