Something to ponder upon: Suppose you are on a gameshow. The host shows you three doors, marked 1,2, and 3. He says there is a car behind one of them, and nothing behind the others. He allows you to choose one door, and you can keep whatever is behind it. You choose door number 1. The host opens up door number 2 and reveals there is nothing behind it. Then he allows you to switch to door 3. Should you?
SPOILER ALERT: You should switch. There is a 2/3 chance that its behind door 3, and a 1/3 chance it's behind 1, your original choice. It's really hard to explain why this is true, so look it up.
From the Darwin awards website (I've changed the exact wording but all the main details are the same)-
A man armed with a pistol walked into a store and proceeded to demand that the owner gave him all the money in the till as a shopper in the store and an onlooker outside watched. Little did the man realise the shop he was robbing was a gun store so the owner pulled out a high powered rifle, the elderly shopper pulled out a revolver she had bought a few minutes earlier and the onlooker was an armed policeman. He left the shop with more holes than he'd gone in with and was a bit dead shortly afterwards.