Henry's Tarzan joke reminded me of another...
Two guys were sitting in a bar, in a skyscraper restauraunt in some city or another. Anyway, the bar was on the twentieth floor. So one guy turns to the other and says, "You know there's something amazing about the air currents around this building. You can jump out of the window, and the currents will bring you back up." The other man guffawed and said, "You're a drunken loon. There's no way that could happen." So the first man turned to the second and said "I'll prove it to you. I bet you fifty bucks that I can jump out that window and I'll come right back up." The second man says, "Okay, just make sure you put your money out now." The first man places fifty bucks on the table and jumps out the window. A few seconds later, he comes back up. The second man is flabbergasted. "Double or nothing," he says. "That was a fluke. You can't do it again." So the first man puts another fifty bucks on the table and jumps out of the window. A few seconds later he returns. The second man pays him $100, shaking his head in amazement. He says "This is amazing, I have to try this." He jumps out of the window, and lands with a splat on the pavement.
The bartender turns to the first man. "You sure are mean when you're drunk, Superman.