Geocache!

If you haven't tried geocaching you should check it out.
It's a treasure hunt using your GPS :)
You will be amazed at all the treasures hidden on your regular walking paths, hiking destinations, and even right around your house!

The concept is easy.  Someone hides something and you find it.

What you might find:

• Log book and pen to record your visit
• Themed cache (take something, leave something)
• Cash prize for the 1st find
• Coordinates to another cache (for a great hike)
• Travel Bug (moves from cache to cache)
• Something totally awesome

You will find everything you need here: http://www.geocaching.com/
If you click on Hide and Seek a Cache and enter your address/location it will bring up all the caches in your area.  You will have to create a login in order to see the coordinates, but it will only take a minute.

Don't forget that most GPS receivers are accurate from 10-50 ft. so once you arrive at the location, you will have to look around for the cache.  Some caches have a hint online in case you need it.  Also, don't let any muggles see you! ;)

You may even want to hide a cache yourself. Happy hide and seeking!  :P