One of the interesting things the spread of the Internet has done is allow the development of hobbies that wouldn't be practical otherwise. One of these is bill tracking. The idea is a simple one. You take the serial numbers off paper money and enter them and your location into a database on a website. You then mark the bill with the URL for the website, spend it as you usually would, and with luck someone who gets that bill will be curious enough to enter it into the system, allowing you to see where its been. I've been entering bill into Where's Willy, a Canadian money tracking site, for a while now. Its a spinoff of Where's George, a site set up by a fellow named Hank to do the same thing with American money. Its cool to enter a bill here in Saskatoon, spend it, and then have it turn up in Pugwash, Nova Scotia. Its a lot more effective system than, as I would occasionally do, mark an X someplace on the bill and hope you run across it again. FYI Willy is a reference to Canadian Prime Minister Sir Wilfred Laurier, who is pictured on the Canadian 5 dollar bill.