Two blokes are in a bar on top of the Empire State Building. One says to the other You know, if you jump off of this building you get sucked in at the 10th floor. The other one laughs and says No way, man. Prove it

The first guy agrees and they both go to the edge. He jumps off and whoof! He gets sucked in at the 10th floor. When he gets back to the top the second guy, standing in shock, says I dont believe it! Let me try.

So the second guy jumps off and splat! He falls to his death. The first guy goes back into the bar. When he gets back there, the bartender tuts and says You know Superman, you can be a real bastard when your drunk!