wheresgeorge.com sounds like a website for discovering the location of outgoing president George W, but in fact it lets you discover where the dollar bills in your pocket have been and track where they end up. Just enter the serial number of a bill along with its series year and then you can see where that bill has been, or at least you can see where it was when other people used wheresgeorge to update the status of that bill. The website claims to track more than 144 million bills of all denominations (not just the dollar which has George Washington on it).
Last week I received a dollar bill that had been marked in the corners with wheresbill stamps, as shown. According to wheresgeorge, the bill was in Las Vegas on 26th December, when incidentally I was also there too. However, the bill then travelled 239 Miles in 21 Days, 6 Hrs, 58 Mins (an average of 11 Miles per day) before it made it into my posession. I have spent the bill already. Who knows where it will turn up next, but if someone else updates its entry on wheresgeorge I'll find out.