A man walks into a bar, he has a couple drinks before meeting a man in glasses who says "Hey, I bet you fifty bucks I can fly out that window right now."
The man takes the bet, the man in glasses would chicken out for sure, they are 10 stories up after all. They shake on it and then the man in glasses goes to the window, opens it, and jumps out. He continues to hover there for a moment then comes inside and collects his winnings from the stupified loser.
A short time later the first man walks up to the man in the glasses and says "Okay, you got me, now how did you do it?" The man in glasses laughs and finishes his drink.
"Anyone can. See, the updrafts from the sewer grates are so strong they just make you float right there instead of falling. Try it! It's a real rush."
The man thinks it over, shrugs, opens the window and dives out. Falling 10 stories to his death.
The barkeep walks up next to the laughing man in glasses and sighs.
"You are one sick bastard, Kent."