Amy: Sheldon, that's enough.
Sheldon: Oh, yeah, no, fine. Let's just agree that both creations are special in their own way and it is foolish to try and compare them. Although, we didn't need to have sex with Howard for ours, so we win.

Leonard: Oh, it's just nice to be with people who are happy to have me around. Isn't that right, Halley?
*Halley starts crying*
Howard: Well, at least someone had the courage to say it.

Amy: What are you looking at?
Sheldon: Comments from our Behind the Flags retrospective. Get this, people are calling it "the longest one yet".

Colonel Williams: I'll cut to the chase. The Air Force believes there's an application for this technology, and we're interested in funding your research.
Howard: Well, thanks, but you should know we're a little concerned about this being used in weapons.
Colonel Williams: Oh, well, let me put your mind at ease. What we use it for is none of your business.

Penny: You can stay in Leonard's room, and we'll stay at my place.
Amy: You're sure that's not an inconvenience?
Penny: No, not at all.
Leonard: And we live with Sheldon, so the word "inconvenience" has really lost all meaning.

Amy: Aww, I remember signing our first Relationship Agreement.
Sheldon: You seem to be forgetting the "no nostalgia" clause.

Penny: It's not that I want to go, I just think it'll make Leonard happy. And if I have to watch him squeeze into an Ewok costume, so be it.
Amy: Look at you, going to Comic-Con, talking about Ewoks. I really have become the cool one around here.

Bernadette: You know, I just read that a team at MIT developed a device that helps people read human emotions.
Leonard: And you think we can get those guys to reprogram Sheldon? Cool.

Amy: What are you doing?
Sheldon: I'm just contemplating Buridan's donkey.
Amy: I understand. I'll leave you be.
Sheldon: What, you're familiar with the reference?
Amy: Of course. Jean Buridan proposed a philosophical thesis stating that a hungry donkey placed between two equidistant bales of hay would be paralyzed by indecision and would starve to death.
Sheldon: Exactly.
Amy: Well, I wouldn't want you to starve to death, so here's an eggplant.
Sheldon: Thank you.
Amy: You know, some people believe that Buridan was plagiarizing Aristotle.
Sheldon: Really?
Amy: Although, in Aristotle's example, he proposed an equally hungry and thirsty man caught between food and drink.
Sheldon: Huh. Yeah, I wonder if that's related to the 12th century Persian philosopher, Al-Ghazali and his story of a man caught between two dates.
Amy: Are you suggesting Al-Ghazali was Aristotelian? 'Cause if anything, he was anti-Aristotelian.
Sheldon: Al-Ghazali was anti-Aristotelian? Boy, you think you know a guy.

Penny: Do boys have flowers?
Leonard: Who knows what he has down there.

Sheldon: No matter where I am, this will always be my spot.

Penny: Oh, that's a nice offer.
Zack: You know, we'd make a great team. Or as we say in the menu business, I can't do this without Me N U.
Penny: Right, 'cause it spells "menu."
Zack: Yeah, right? It's funny. I got a lot of menu jokes, but that's my favorite.

Leonard: You know what? There is one thing I would like.
Sheldon: Yeah, take whatever you want.
Leonard: I would like to keep the official flag of our apartment.
Sheldon: But you don't even like flags.
Leonard: Yeah, I like this one.
Sheldon: But I designed it.
Leonard: But you made me order it because you were "too well-known" in the flag community and they'd jack up the price.
Sheldon: But you don't even understand its symbolism.
Leonard: Oh, I do. The-the field of blue represents you being miserable, and the lion sticking its tongue out means I'm happy about it.

Bert: Okay, well, thanks for coming by. You're nice people.
Penny: Well, so are you. In fact, you know what? We will never take you for granite. Did you get that? Granite? A little geology joke.

Leonard: It's not that I'd stopped trying, it's just how relationships progress. They start with infatuation, but over time mellow into something more comfortable.
Sheldon: Hmm. Yeah, you're right. It's like when I first encountered the Pythagorean Theorem. You know, I was blown away that the square of the hypotenuse was the sum of the squares of the opposite sides. Yeah, but now I'm just like "eh."