This has been copied by South Park, Peanuts, The Simpsons, Family Guy... I read somewhere that Joe Pesci started ad libbing, and the rest of the scene evolved from there. Whatever the truth of the matter, it's one of the most memorable scenes from recent cinema:
Unfortunately, the megalomaniacs at Warner apparently requested embedding to be disabled on all the other YouTube versions of this scene, and this one doesn't include Pesci's "funny story," as well as having all the expletives bleeped out, leaving precious little dialogue!
I'll tell you what: here's the transcript...
TOMMY: What's really funny was that fucking bank job in Secaucus. I'm in the weeds lying down.
He said, "What are you doing?" I said, "Resting." Here? In the weeds? I'm resting!
They pull me in, start asking questions. You know, this and that. "What are you going to tell us?" I said, "My usual. Nothing. Why tell you?" The fuck. He says, "No, you'll tell me something today." I said, "Okay, go fuck your mother."
You saw the paper. My head was out like this [indicates massive bruising]. I'm coming around and who do I see in front of me? This prick again. He says, "What do you want to tell me now?" I said, "What are you doing here? I said to go fuck your mother."
I thought he'd shit. The fuckers. I wish I was big just once.
HENRY: Funny. You're really funny.
TOMMY: What do you mean?
HENRY: It's funny, you know. It's a good story. You're a funny guy.
TOMMY: You mean the way I talk? What?
HENRY: It's just, you know. You're just funny. You know, the way you tell the story.
TOMMY: Funny how? What's funny about it?
ANTHONY: You got it all wrong.
TOMMY: He's a big boy. He knows what he said. Funny, how?
HENRY: Just, you know. You're funny.
TOMMY: Let me understand this. Maybe I'm a little fucked up. But I'm funny how? Funny like a clown? I amuse you? I make you laugh? I'm here to fucking amuse you? What do you mean, funny? How am I funny?
HENRY: You know, how you tell a story.
TOMMY: I don't know. You said it. You said I'm funny. How am I funny? What the fuck is so funny about me? Tell me what's funny.
HENRY: [Long pause while Henry assesses the situation] Get the fuck out of here, Tommy.
TOMMY: Motherfucker! I almost had him. You stuttering prick, you. Frankie, was he shaking? I wonder about you sometimes, Henry. You may fold under questioning.