Sheldon: Leonard, are you in bed?
Leonard: Yes.
Sheldon: Me, too.
Leonard: Great.
Sheldon: I can't sleep.
Leonard: Well, I can, so shut up.
Sheldon: Do you realize that in less than nine hours, Arthur Jeffries, aka Professor Proton, will be in our apartment?
Leonard: Sheldon, you know that if you stay up all night, you're gonna be sleepy tomorrow. And a sleepy Sheldon is a cranky Sheldon. And a cranky Sheldon is actually no different than a regular Sheldon. Good night.

Leonard: Penny, as a scientist, my job is to figure out why things happen. But I don't think I'll ever understand how someone like me could get to be with someone like you. You know maybe I don't need to understand it, I just need to be grateful. I love you, Penny.

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.

Professor Proton: Okay, as, as I put the egg on top, and, and the flame goes out and, and, and the air pressure decreases in, in the flask, what do you think will happen?
Penny: I think I know.
Sheldon: It's gonna get sucked in. It's going to get sucked in.
Penny: Okay, I didn't know.
Sheldon: Yes!
Penny: See, I'm not a scientist like them.
Professor Proton: I, I figured that out.

Professor Proton: I'm having trouble with my pacemaker.
Leonard: I'll call for help.
Penny: Any chance we could plug it into the potato?
Professor Proton: No.

Howard: How'd you get him to come to your house?
Sheldon: As Professor Proton always says, there is no problem you can't solve if you use your noggin.
Leonard: And he wrote him a check.
Sheldon: Yeah, that too. A big check.