One of my favorites only got honorable mention a few years ago:
"A man walked into a Circle-K in Louisiana, put a $20 bill on the counter and asked for change. When the clerk opened the cash drawer, the man pulled a gun and asked for all the cash in the register, which the clerk promptly provided. The man took the cash from the clerk and fled, leaving the $20 bill on the counter. The total amount of cash he got from the drawer was $15. Question: if someone points a gun at you and gives you money, is a crime committed?"
And ... I always thought the story about the man who flew his lawn chair up to 16,000 feet above Los Angeles was an urban legend, but according to Darwin, it's true. Click here for the story.