A string walks into a bar & asks the bartender for a beer.
The bartender grins, saying "we don't serve strings in this bar."
The string walks outside, ties himself in a knot and messes up his hair. He then proceeds to walk back in and asks again for a beer.
The bartender asks, "Hey, aren't you that string that was just in here?!"
The string replies, " No, I'm a frayed knot."