The basic idea around Geocaching is to have individuals and organizations set up caches all over the world and share the locations of these caches on the internet.
GPS users can then use the location coordinates to find the caches. Once found, a cache may provide the visitor with a wide variety of rewards.
This is pretty fun.
Where to get GPS Coordinate for caches based on ZIP CODES.
Geocaching
Cool GPS Units.
Garmin
My Fav GPS
