Sheldon: This place is terrific. Why have we never been here before?
Leonard: The same reason we don't do a lot of fun stuff - you.

Howard: Lots of people wear matching pajamas who aren't dating.
Raj: Like who?
Howard: Like you and your dog.
Leonard: Don't rule out the dating.

Leonard: By the way, my leg is killing me. Thanks for asking.

Leonard: Come on, she's your friend. Step up! [Knock * 3] Amy. [Knock * 3] Amy. [Knock * 3] Amy. (Turns to leave) Bye!
Sheldon: Where are you going?
Leonard: I'm single, I don't need this crap.

Penny: Thanks for cooking.
Leonard: My pleasure.
Penny: That carrot was delicious.
Leonard: Yeah. I wish I'd fought harder for the rest of 'em.

Leonard: Thanks for closed captioning my pain, Raj.

Leonard: Okay, Sheldon, I understand that youre going through a bit of a career crisis, you're searching for some other area where you can feel valuable and productive but I need to tell you something and I want you to listen carefully.
Sheldon: All right.
Leonard: Go away!

Sheldon: Oh Lord, this can't be more humiliating.
Leonard: No, no, no, give him a minute.

Leonard: Going to Wheaton's party is not betraying you.
Sheldon: Oh, of course you would have to believe that. Evil always thinks it's doing right. Excuse me, Stormtrooper. These are the droids you're looking for.
Leonard: I'm going to a party. I'm not turning R2-D2 and C-3PO over to the empire!
Sheldon: Not yet.

(Sheldon repeatedly knocking and saying Leonard's name)
Leonard: Ugh, this would be so much easier if I were a violent sociopath!

Amy: Is he always like this when he loses?
Sheldon: Oh, yes. You should have been here for the great Jenga tantrum of 2008.
Leonard: You bumped the table and you know it.

Leonard: You may be from Texas, but I'm from New Jersey.

Leonard: Sheldon, we've been together so long, it's hard to remember a time you weren't in my life. And believe me, I try.
You make me laugh.
You make me a better scientist.
You make me crazy.
You're more than just my roommate, you're my brother.
Sheldon: Thank you.
Leonard: Happy birthday, buddy.

Leonard: I wonder if that's why I have such a dysfunctional relationship with Sheldon. I had a dream the other night that I was in a cave, and I was nursing a baby. But the baby had Sheldon's head on it.
Mandy: And your wife is worried about me?

Leonard: Some kind of nerd? I'm the king of nerds.
Penny: What does that mean?
Leonard: It means that if someone makes me mad, I won't help them set up their printer.