One night a man decides to visit his local bar. He takes a seat and 
orders a beer. After polishing off his beer, he beckons the bartender 
over and says, "Betcha $20 I can bite my eye."     
The bartender scoffs and accepts. The man then calmly removes his false 
eye and bites it. The bartender grudgingly forks over a twenty. 
 
Later that night, after a few more beers, the man wanders back to the 
bar and says rather drunkenly, "Hey barkeep, betcha another $20 I can 
bite my other eye." 
Wanting to win back his money and seriously doubtful that the man has 
two false eyes, the bartender accepts. The man calmly removes his false 
teeth and bites his other eye. Scowling, the bartender hands over 
another twenty.      The man leaves and wanders around the bar as he 
drinks a few more beers. 
 
He strolls back over to the bar, leaning on it, again and calls the 
bartender, "Hey, barkeep," he says,  "I'll give you a chance to win 
your money back plus. Betcha $100 if you put a shot glass on that end of 
the bar, and I stood on this end, I could piss into it and not spill a 
drop."   
The bartender eagerly accepts, knowing the feat to be impossible. The 
man wobbily climbs atop the bar, pissed 
all over the bar.
"What's so funny?" says the barkeep. "You just lost everything you won and more!"    
Well," giggles the man, "I just bet those guys over there $200 that I could piss all over your bar and you wouldn't get angry."