A guy walks into a bar and starts talking about how jokes work and how you can make jokes based on that. He talks about jokes within jokes, and never-ending cycles of meta-jokes.
He talks about the nature of humor and the essence of jokes. He talks about philosophy, and religion, and language.
After a while the bartender gets bored, and tries to change the subject. But the guy just keeps going on and on about meta-humor.
Finally the bartender says "Alright, enough already. I'm sick of this," and he kicks the guy out of the bar.