Leonard: I'm going to the movies with Penny. I don't want her to think I think it's a date.
Sheldon: Do you think it's a date?
Leonard: No, but she might think I think it's a date even though I don't.
Sheldon: Or you might think she thinks you think it's a date even though she doesn't.
Leonard: Are we over thinking this?
Sheldon: Not at all.

Leonard: Star Wars on Blu-ray.
Penny: Haven't you seen that movie like a thousand times?
Leonard: Not on Blu-ray. Only twice on Blu-ray.
Penny: Oh, Leonard.
Leonard: I know, it's high resolution sadness.

(Leonard is pointing out the monotonous movie habits of their former relationship.)
Leonard: No. You always picked, and it was always the same. An hour and a half of beach houses in the rain until the woman turns around and realizes love was here all along.
Penny: But, come on, that is a great movie, and it starts in ten minutes.

Tom: I'm sorry, dude, she didn't look anything like her picture.
Leonard: They never do.

Leonard: So if you are considering going into experimental physics, my door is always open. Once again, I'm sorry that the demonstration didn't quite work out. But now we know what happens when you accidentally spill peach snapple into a helium-neon laser. The short answer is don't.

Penny: What is this?
Leonard: Oh, careful. That's my original series Battlestar Galactica flight suit.
Penny: Oh, why didn't you wear it on Halloween?
Leonard: Because it's not a costume, it's a flight suit.

Howard: So who wants to rent Fiddler?
Sheldon: No need. We have the special edition.
Leonard: Well, maybe we are like Haroun and Tanweer.

Leonard: I was thinking more of a biosocial exploration with a neurochemical overlay.
Leslie: Wait, are you asking me out?

Doug: What's up, bro?
Leonard: Uh, nothing much... Bro!

Sheldon: Whoo! I'm all sweaty. Anybody wanna log on to Second Life and go swimming? I just built a virtual pool.
Leonard: No, I can't look at you or your avatar right now.

Leonard: Elevators, parks, movie theaters. Out of curiosity, is this subway, the transportation system, or Subway, the sandwich shop?
Penny: Sandwich shop.
Leonard: Doesn't that violate the health code or--?
Penny: No, at the sandwich shop, we were only making out.

Raj: Did the listing actually saying "Miniature"?
Leonard: (Looking at time machine) I just assumed.

Leonard: It's kinda like the Loch Ness Monster. Maybe there's something there, maybe there isn't. We'll never know but sometimes it's fun to creep yourself out thinking about it.

Leonard: Sheldon, we both agreed to do this.
Sheldon: It's a waste of time. I might as well explain thermodynamics to a bunch of Labradoodles.
Leonard: If you don't do this, I won't take you to the comic book store.

Leonard: That's it, no more Thai food.