Geocaching - the Ultimate Outdoor Game. This is where hiking meets treasure hunting and your GPS unit. You start by locating a cache near you (the website will help you find one), obtain coordinates, plug the coordinates into your GPS unit, and then hike to the spot, and see if you can find the treasure that's hidden there. Does this sound like fun? Well, it is (don't listen to my kids).
Under construction. More to come later: hiking, astronomy, etc.