If you ever collected Magic: The Gathering cards, you might want to take a look and see if you have the Black Lotus card. One copy of it, rated 9.5 out of 10 by Beckett Grading Services, recently sold for $27,302 on eBay.
The seller described the card as "the holy grail of non sports cards in the finest condition ever graded by BGS." According to an article at the A.V. Club, "it is believed that only 1,100 of these cards were printed during Magic's very limited first run in 1993."
If you do find a Black Lotus card in your M:tG collection, take a deep breath: There are also second-edition Black Lotus cards which, presumably, are worth considerably less. (About 3,300 second-edition cards were printed.)