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: You'll never guess what just happened.
Sheldon: You went out in the hallway, stumbled into an inter-dimensional portal, which brought you 5,000 years into the future, where you took advantage of the advanced technology to build a time machine, and now you're back, to bring us all with you to the year 7010, where we are transported to work at the think-a-torium by telepathically controlled flying dolphins?
Leonard: No.
Sheldon: Awww.
Leonard: Penny kissed me.
Sheldon: Who would ever guess that?

Penny: What do you mean new roommate? What happened to Leonard?
Sheldon: The same thing that happened to Homo Erectus. He was replaced by a superior species.
Raj: I'm the new homo in town.

Raj: I've said this before and I'll say it again: Aquaman sucks!

Zack: Whoa, you dated Penny?
Leonard: She didn't tell you?
Zack: She told me she dated a guy named Leonard. Who would have thought it was you?
Leonard: Who else would it be?
Zack: I don't know. Somebody bigger and- Yeah, sure. Why not you?

Mary Cooper: Now, when you said on the phone he broke up with a girl, you meant an actual girl? Not something you kids whipped up in a lab?

Penny: Oh, big deal. Not knowing is part of the fun.
Sheldon: "Not knowing is part of the fun." Was that the motto of your community college?

Howard: Hell hound.
Raj: Who let the satanic dogs out?

Sheldon: I'd like to go over some proposed changes to the roommate agreement, specifically to address Penny's annoying personal habits.
Penny: Oh my God! What personal habits?
Sheldon: I have a list. FYI overuse of the phrase "Oh my God" is number 12.

Sheldon: Oh, what fresh hell is this?
Biosuit Nurse: Wait, you can't leave here, you've been exposed.
Sheldon: (Covering his face with his shirt) No, I haven't. It's all good.

Penny: So that means, you're a doctor, you're a doctor, you're a doctor, you're a doctor and, Howard, you know a lot of doctors.

Wolowitz: Raj, did you ever tell your sister about the time Sheldon got punched by Bill Gates?
Priya: Oh, God, you're kidding.
Raj: No, Gates gave a speech at the university. Sheldon went up to him afterwards and said, "Maybe if you weren't so distracted by sick children in Africa you could have put a little more thought into Windows Vista."
Leonard: Bam, right in the nose. Made me proud to own a PC.

Leonard: I'd suggest using some lubricant, but I have a feeling you fell on that as well.
Howard: Not funny, Leonard.
Raj: Really? A robot hand’s got a death grip on your junk, dude. That’s funny, ask anyone.

Althea: What is this?
Howard: It's a robot arm.
Althea: Where's the rest of the robot?
Howard: I only built the arm.
Althea: Because that's all you needed, right?

Zack: You know, I saw this great thing on the Discovery Channel. Turns out if you kill a starfish it'll just come back to life.
Sheldon: Was the starfish wearing boxer shorts? Because you might have been watching Nickelodeon.