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

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?

Amy: I find the notion of romantic love an unnecessary cultural construct that adds no value to human relationships.

Zack: Hold on. The costume came with a black wig.
Penny: No. I'm not wearing it. It looks stupid.
Zack: Come on. We're trying to win a contest here.
Penny: Forget it. I'm not wearing the wig.
Zack: Honey, there is no "I" in "Justice League."

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.

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?

Sheldon: Jacuzzi is a commercial brand, hot tub is the generic term, i.e., all Jacuzzis are hot tubs, but not all hot tubs are Jacuzzis.
Zack: Is that like all thumbs are fingers but not all fingers are thumbs?
Sheldon: Surprisingly, yes.
Zack: Nice! Now what exactly are toes?

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: On the potty, what are you five?
Raj: It's a potty, what do you call it?
Howard: A toilet.
Raj: That's a little vulgar for the dinner table, don't you think?
Howard: And potty is okay?
Raj: Potty is innocent. Potty is adorable.
Howard: What do you do on the potty, wee-wee?
Raj: If I don't have to boom-boom.

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.

Raj: Cute is for bunnies. I want to be something with sex appeal. Like a labradoodle.

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.

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?

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.