A man walks into a bar and orders a drink. As he's sitting there enjoying his beverage, he notices a tiny man playing a tiny piano on the bar. Intrigued, he asks the bartender about it.
The bartender explains that the tiny man is actually a genie who grants wishes to anyone who can make him laugh. The man decides to give it a shot and walks over to the tiny piano player.
He tells his best joke, but the tiny man doesn't even crack a smile. Undeterred, the man tries another joke, but still no reaction. He keeps telling joke after joke, but the tiny man just sits there stone-faced.
Finally, the man gets frustrated and yells, "Why won't you laugh? I've told you all my best jokes!"
The tiny man looks up at him and says, "Sorry, buddy. I can't laugh at your jokes because I've heard them all before. I've been stuck in this bar for centuries, and let me tell you, genie humor gets old real fast."