Two fraternity brothers decide to go sailing one afternoon and become lost. After twenty hours with nothing to eat or drink, one of them spots a lamp floating by. He picks it up and a genie pops out. The genie notices the poor condition of the brothers and grants them one wish between the two of them. 

After a lot of arguing over who gets the wish, one of them blurts out, "I wish the ocean was made of beer." 

Magically, the ocean turns to beer. 

Infuriated, the other guy yells, "You idiot! Now we have to piss in the boat!"