I sensed (well, OK, I checked the blogstats) that the recent Math Magic posts on Mindreading were getting a lot of hits. So for fun, here* is another mind-reading site. In this one you are shown some cards, you pick one, and the computer uses amazing powers (mind-reading and/or listening skills) to determine which card you picked and remove it from the selection. There’s no actual math in this one, although searching for it did reveal even more sites that do combine math and mind-reading, so there’s plenty of fodder for future entries on this topic!
* This site seems to have a lot of advertising on it, though I know I’ve seen less commercial sites with the same trick.