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?

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: Answer the phone, Leonard.
Leonard: No! There, it went to voice mail.
Sheldon: Aren't you going to check your messages?
Leonard: No.
Sheldon: You have to check your messages, the leaving of a message is one half of a social contract which is completed by the checking of the message. If that contract breaks down then all social contracts break down and we descend into anarchy.

Leonard: Well, what are you gonna do?
Howard: I'm gonna figure out how to fix it, then I'll tell them.
Leonard: So, what do you need us for?
Raj: He can't figure out how to fix it.
Howard: Hey, you said you were gonna be supportive.
Raj: I'm trying, but you have to admit this is pretty damn funny.
Sheldon: I agree. It's the juxtaposition of the high-tech nature of space exploration against the banality of a malfunctioning toilet that provides the comic fodder here. Check your messages.

Leonard: Thanks for closed captioning my pain, Raj.

Penny: What the hell is that?
Howard: Meatloaf.
Leonard: What was it doing on the ceiling?
Howard: That's classified.

Penny: Morning. What’s up?
Leonard: Nothing. We just pulled an all-nighter trying to fix a zero-gravity ... pasta maker.

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!

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.

Raj: Howard, wait. Why don't you use this instead of the PVC to keep the transverse filter assembly in place?
Howard: Because this is not a spare part from the space station. This is the thing from the pizza box that keeps the lid from touching the cheese.
Raj: That what that's for? In India, the lid just touches the cheese. Of course, we also have rampant poverty and periodic outbreaks of cholera, so a little cardboard in our cheese is no biggie.

Stuart: Uh, hey, Leonard, can I talk to you about something?
Leonard: Oh, sure, what's up?
Stuart: Remember I went out with your friend Penny a couple weeks ago?
Leonard: Yeah, vaguely.
Raj: Sure you remember. You went to the bar and made a fool of yourself trying to pick up strange women.

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.

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

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.

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