GPS technology is good for more than just directions. For outdoor fun, try geocaching, an adventure game for GPS users. Individuals and organizations around the world create caches and then place cache coordinates on the Internet. Other GPS users visit the caches and sign a guest book, or take an item and leave an item. Caches are often placed in locations that are interesting or challenging to get to.
You can search for geocaches in your region with a simple search utility (requires free registration).
Caches are rated by size, difficulty, and terrain. Those who list caches can include as many hints as they wish. Cache locations range from easy finds in urban parks, to summits of difficult mountain climbs. Other popular categories include urban parks, historical sites, wineries (why not?), covered bridges… you get the idea.
The final part of the fun is going online to comment on the cache and to see what others have written about it.