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: 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?

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.

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: 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?

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.

Penny: Well, In that case, do you mind giving me some advice?
Leonard: About Stuart? Love to.
Penny: He's very shy, how do I make him feel more comfortable around me?
Leonard: Well, uh, first of all, don't underestimate the value of discomfort.
Penny: Really?
Leonard: Well, yeah, Stuart thrives under pressure, that's why he works in a comic book store.

Leonard: Oh. It's Stuart.
Sheldon: You're not going to answer it?
Leonard: He wants to talk about Penny. I don't want to talk about Penny.
Sheldon: You're making an assumption. Perhaps the comic book store is on fire, and he needs your assistance.
Leonard: Why would he call me?
Sheldon: We don't know. And if you don't answer the phone, we can't know.

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.

Howard: Look, I was going over the schematics on my zero-G toilet, and I made a teeny tiny mistake on the specifications for the diverter valve.
Leonard: How teeny tiny?
Howard: It's gonna fail after about ten flushes.
Sheldon: But the mission is for six months.
Howard: Yeah, see, that's the code red. It's kind of like a jack-in-the-box, no one knows exactly when, but at some point something way worse than a puppet is gonna pop out of that box.

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: Hey Stuart.
Stuart: You busy?
Leonard: Um…
Howard: Classified, Leonard.
Leonard: Yeah, it's a regular Manhattan Project.

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.

Raj: Okay, look. Instead of trying to reinforce this structure here, what if we just ran another line, bypass it entirely?
Sheldon: It won't work. The diameter of the tubing is insufficient.
Raj: What if we reposition the collection tank?
Sheldon: It won't work. No way to mount it.
Howard: Okay, here's an idea. What if I change my name and go live with my cousin and her husband Avi in Israel?
Sheldon: That could work.