I saw this yesterday and had to share:
Banterist - eBay: Drive Someone Insane with Postcards
At one point in the past my grandmother was getting postcards similar to those from a stranger sent from random places around the world. I don't think she ever found out who it was, but it sure makes for an awesome story. I think you'd be hard-pressed to find a better use of your money than bidding on that auction.