Penny: Well, I'm going to take myself out to a movie tonight. You want to go?
Leonard: Really? Do we do that?
Penny: What do you mean?
Leonard: You know, we haven't spent time alone together since we broke up.
Penny: Oh, it's not a date, Leonard. It's just a man and a woman hanging out, and not having sex at the end of the night.
Leonard: Sounds like most of my dates.

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.

Sheldon: This song is never going to stop. Have you ever dealt with something so relentlessly irritating?
Leonard: That's a trick question, right?

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.

Amy: If you're keeping him, I've got a cage you can borrow. One of the test monkeys slipped on a banana peel and broke his neck. It was both tragic and hysterical.

Sheldon: Get back here, you stupid bird, so I can love you.

Penny: Really? On top of everything, you're afraid of birds?
Sheldon: Its called ornithophobia and someday it will be recognized as a true disability, and the landlord will be required by law to put a giant net over the building. Which is unfortunate because I have a fear of nets.