Howard: (To Raj) Will you play the ukelele?
Raj: Sure, I'd be happy to shred it on my axe.
Howard: Or you could just play your tiny, ridiculous guitar.

Sheldon: They called it the greatest thing since the Communist party. Although I'm pretty sure the Communist party made them say that. I like China. See, they know how to keep people in line.

Penny: What are you working on?
Sheldon: Can't talk. In the zone.
Penny: (To Amy) Do you know what he's doing?
Amy: Could be anything. Last time he was like this he figured out electron transport in graphene. The time before that he was making a list of who's allowed in his tree fort if he ever gets one. Still can't believe I didn't make the cut.

Penny: Sheldon, you wanna take a break? Your food's ready.
Leonard: What are you doing? He's both happy and quiet. It's like seeing a unicorn and big foot at the same time.

Bernadette: Great news. A raccoon virus just crossed the species barrier and can now infect humans.
Raj: Why is that great news?
Bernadette: In the pharmaceutical business we have a saying: mo' infections, mo' money.

Penny: Aww, what horrible thing are you trying to make up for?
Howard: Just putting something in the bank for what horrible thing I do next.

Penny: How come you've never done anything romantic to celebrate our first date?
Leonard: For starters, you've broken up with me so many times, which first date are we talking about?
Sheldon: Oh, somebody call the burn ward. ... And back to the zone.

Penny: Okay, what happened between you and Amy?
Sheldon: Can you believe she said I embarrassed her?
Penny: Yeah.

Leonard: Sheldon, I've known you a long time. I'm going to tell you this with all the love I can possibly muster. Amy's right, you're wrong.
Sheldon: But you don't even know -
Leonard: It doesn't matter.
Sheldon: But in my defence -
Leonard: Doesn't matter!

Sheldon: You want some mutton and coconut milk?
Amy: No.
Sheldon: Boy I can not give this stuff away.

Sheldon: Amy, this isn't easy to say. All relationships are difficult. But even more so when you're with a person who struggles with everyday social interactions. And frankly, who can strike people as being kind of a weirdo.
Amy: Sheldon, you're not a weirdo.
Sheldon: I wasn't speaking about me. I mean, honestly, there's no telling what will set you off. Introducing myself as your boyfriend. Giving you the opportunity to drive me home. Breaking the ice with you colleagues using ethnic humor - the funniest kind of humor.

Sheldon: My point is we're a couple and I like you for who you are - quirks and all.
Amy: I like you too.
Sheldon: I should hope so. I don't see anybody else banging on this door to put up with your nonsense.
*Amy slams the door on Sheldon*
Sheldon: Not even a goodbye? You see this is the kind of thing that makes people think you're weird. ... Poor kid. She just doesn't see it.

Sheldon: Maybe your friend Gundersen needs to head over to IKEA and assemble a sense of humor.

Sheldon: Did you know that Los Angeles has a little Sri Lanka?
Leonard: I did not.
Sheldon: Well, I do now. They're a lovely people, although terrifying when you wake up face to face with them.

Sheldon: If you're hungry, I brought home mutton and coconut milk.
Penny: Why'd you do that? You hate lamb.
Sheldon: I was asking for directions. Apparently there was a communication problem.