A string walked into a bar. He went up to the bartender and asked for a glass of vodka. The bartender said, "I'm sorry sir but we do not serve strings in this bar."

So the string went outside, tied himself in a knot and ruffled out his top and bottom. He went back into the bar and asked, again, for a glass of vodka. The bartender said "Aren't you that string that was just in here a minute ago"

The string looked him in the eye and said, "No, i'm afraid not." (a frayed knot)