There’s a dollar in my wallet (that’s true on so many levels… well, two levels) that looks like so:
See where I’ve been
Track where I go next
Which I think is a pretty cool idea… especially as it depends entirely upon me even noticing or being interested in the defacement of my currency. In going to this site, I found that it was last seen in Jamestown, North Dakota, some 105 days ago, and had traveled 1,362 miles at a rate of 13 miles per day. Not bad for no legs.
Of course, the success of this site depends upon people being conscientious about entering in all of their money (luckily I have very little), but it was interesting nonetheless.