Leonard: What are you guys doing?
Sheldon: Oh, well, we decided to use our breakfast time to expand our respective knowledge bases.
Leonard: Oh, let me try.
Penny: Okay.
Leonard: Hmm. Atom of hydrogen. Adam of Maroon 5. Mic drop.
Sheldon: I'm sorry, who is Mike Drop?

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.

Penny: Helium.
Sheldon: Yes.
Penny: Yes.
Sheldon: Taylor Swift.
Penny: Yes. Pi.
Sheldon: Yes. Kardashian.
Penny: More specific.
Sheldon: Khloe?
Penny: Yes.
Sheldon: See, I remembered because if it looks like Kim it's Kim, if it looks kind of like Kim it's Kourtney, and if it looks nothing like Kim it's Khloe.

Stuart: Anyone else need anything before I go?
Howard: I'll give you a dollar if you make fun of Raj.
Stuart: That's mean.
Howard: Five.
Stuart: You look like Tigger if Tigger looked like a jackass.
Howard: Uh, if you ever need a reference or anything, just let me know.

Raj: Boy, all this standing's making me tired. Good thing I brought my collapsible stick chair.
Howard: Not the stick chair. You look like an idiot on that thing.
Raj: Sticks and stones may break my bones, but chairs on sticks are comfy.