Originally Posted by Oneironaut
A piece of string walks into a bar, and orders a drink. The bartender looks up at him and says "We don't serve pieces of string in here. Get out!" The string, dismayed, leaves the bar. The piece of string really wants to get drunk, so he sits on the sidewalk for a while thinking of how he can get a drink at the bar, when he gets an idea. He frays himself up, ties himself into a knot, and goes back into the bar. The bartender glares at him and says "Hey! Aren't you the same piece of string that was in here just five minutes ago?" to which the string replies "No, I'm a frayed knot!"