Geocaching is a game for users of Global Positioning Systems (GPS). The idea is that people set up caches all over the world and GPS users enter waypoints into their systems in an attempt to locate the caches. The cache may be filled with rewards that are available to the player once he or she has found the cache. Rewards include books, CDs, maps, etc. After receiving a reward, the player must then leave something else behind. This Web site is dedicated to the rules of Geocaching and it includes frequently asked questions and a brief tutorial on placing caches.