Three guys are merrily drinking on the top floor of a skyscraper. The first guy staggers over to the edge of the building, and says:
"Ya know that due to the shape of this f..kin building, the wind stops anything falling and brings it back onto the roof?"
The second guy says: "What the f... are you talking about?"
The first guy says: "Is true, the wind races up this side, so you cannot fall.Look, I'll show youse"
To the horror of the second guy, the first guy suddenly leaps over the edge. He falls for ages, but then suddenly slows, and then shoots back up, landing just beside the second guy.
The second guy is amazed. He wanders over to the side, and jumps over. He whistles down, never slows, and then SPLAT on the pavement.
The third guy then says to the first guy: "Superman, you are a f..in mean drunk!"