Penny: Okay, new topic, please. Hey, did you hear the people upstairs in 5A are moving out?
Leonard: Shh-shh-shh!
Sheldon: What?
Penny: The people upstairs are moving out.
Leonard: No!
Sheldon: The horror!
Leonard: Why would you just say something like that?
Sheldon: No, no, no, no, no, no, no-
Penny: How else was I supposed to say it?
Leonard: Slowly, like putting a new fish in a tank. You dont just drop it in, you let the bag sit in the water a while.

Leonard: What would you be if you were attached to another object by an inclined plane, wrapped helically around an axis?
Sheldon: Screwed?
Leonard: There you go.

Leonard: My point is, while you're spending all this time on your own, building computers or practicing your cello, what you're really doing is becoming interesting. When people finally do notice you, they're gonna find someone a lot cooler than they thought. And for those of you that were popular in high school, it's over, sorry. Thank you. Congratulations.

Leonard: [to a "smiling" Sheldon] We're here to see Koothrappali, not kill Batman.

Wolowitz: Penny, let me take this opportunity to point out that you are looking particularly ravishing today.
Penny: Not with a thousand condoms, Howard.
Wolowitz: So there is a number.

Penny: Leonard, and Howard, and Raj, they aren't like other guys. They're special.
Alicia: Okay, they're special, and?
Penny: Well let's see how can I explain this. Um. They don't know how to use their shields.
Alicia: Shields?
Penny: Yeah. You know like in Star Trek and you're in battle, and you raise the shields.
*Realizing what she said* Where the hell did that come from?

Howard: Enough with the guilt, ma. We'll still see each other. I'll come over every night and have dinner with you.
Mrs. Wolowitz The hell you will! What am I running here, a fancy restaurant? Does this look like the Olive Garden?