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.

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.

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!

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.

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.

Sheldon: Smell that? That's the smell of new comic books. Oh, yes!
Howard: They're on me today, boys.
Raj: You're paying? Have you been selling your sperm again?

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.

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.

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

Stuart: Well, tonight's my date with Penny and since we haven't been able to connect by phone...
Leonard: Yeah, I'm sorry, it's been broken.
Stuart: Or e-mail.
Leonard: Yeah, that too. Everything's broken.
Stuart: Anyway, I was just wondering if you had any last-minute advice.
Leonard: All right, well, off the top of my head, I think the most important thing with Penny is to go really slow. I mean, glacial.
Stuart: Okay.
Leonard: You know, guys come onto her all the time, so, you need to, like, set yourself apart. You know, be a little shy, don't make too much eye contact. And, you know, treat her with, like, cool detachment and, you know, fear.
Stuart: Fear?
Leonard: Yeah, like, you're afraid that if you touch her, she'll break.
Stuart: Well, that plays right into my wheelhouse.

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.

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.

Stuart: Yeah, last night at dinner, I did what you told me, I went really slow, I kept my distance, and two bottles of wine later, we were making out in my car.
Leonard: Wine? I didn't say to give her wine.
Stuart: It doesn't matter, that's where it all went to hell.
Leonard: During the kissing? What did you do, sneeze in her mouth? I did that to a girl once.
Stuart: No, everything was good and really hot, and I said “Oh, Penny,” and right where she was supposed to say, “Oh, Stuart,” she said ... your name.
Leonard: Leonard?
Stuart: That is your name, right?
Leonard: Yeah, no, yeah, wow, I'm sorry. That must've been the last thing you wanted to hear.
Stuart: Well, it beats "You know I'm a dude, right?" Yeah, it was pretty bad.

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?

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