When I'm bored, I can look up huge insurance liability claims to see what the story was. Usually its a dog bite, but there are lots of crazy stories in there to prove that people can be really, really stupid sometimes.
Just now looked up a huge claim: insured was in a boat pulling some kids in a tube, doing figure 8's in a lake. Accidentally sent the tube into some rocks, kids went flying.
edit: here's another one. Parents were out of town, 18 year-old son decided to throw a party. Everyone's on the balcony, boozing it up, fight breaks out, someone is shoved over the balcony, boom. Huge medical bills.
Moral of the story: parents, make sure your adult kids don't throw wild parties at your house while you are gone.