Here in Australia I once received a US quarter from the McDonalds drive-tru amongst my change. It was minted in the early 1960's, back when they were still made of silver or something. I looked it up and apparently it was worth several dollars now. At first I was like "HA HA! Joke's on you McDonald's, this is worth more than the twenty cents you were supposed to give me!" but then I was like "ah damn, as if I'm ever going to go to the trouble of selling it. Curse you McDonald's. Curse you."