www.geochaching.com
I have logged seven finds and have introduced three people to it in the past week. Too much fun for real
http://en.wikipedia.org/wiki/Geocaching
You might think you absolutely need some sort of GPS device but that's not necessarily true. I use the map provided and clues and do pretty well. However, my friend, Becky S, has a GPS phone so she has agreed to play too. Yay!
