Being that Foomer mentioned Geocaching a few days ago, I thought I'd mention geodashing. I just found out about this today, so I'm not an expert on this at all, but it sounds very interesting and fun.

Each month, a large set of lat/lon coordinates (called geodashes) are generated randomly by a computer. Because they are completely random, they may not be reachable.

The goal is to find as many of these geodashes as possible. The first person to find the geodash gets 3 points. The 2nd gets 2, and everyone else who finds it gets 1 point. You can go individually, or you can be in a group of up to five people. You must get within 100 meters (about 328 feet) of the location and write down a description of the area and (if possible) take a picture.

At the end of the month, the team with the most points wins. One of the guys in my area is thinking about creating a team. If so, I will probably be on that team.

Website: http://geodashing.gpsgames.org