My wife recently received a US dollar bill and it had a website address stamped on it "WWW.WHERESGORGE.COM" You can track the money and where it has been. I thought it was kind of cool.
At the website above I found links to other sites that track other types of money.
Europe: EuroBillTracker
www.eurobilltracker.com
Germany: Wo ist Mein Geld (Where's My Money?)
www.woistmeingeld.de
(Not operational due to the introduction of the Euro.)
United Kingdom: Dosh Tracker
www.doshtracker.co.uk
Netherlands: Where's The Money?
www.wheresthemoney.nl
Denmark: The Note (or "The C-Bill")
http://www.sedlen.dk/
Japan: Osatsu
www.osatsu.net ("Osatsu" means "a bill" in Japanese.)
Enjoy
