Geocaching is the world’s largest treasure hunt. Using GPS coordinates, you can navigate to a hidden cache, sign the log, maybe grab some trinkets and then move on to the next one. Perfect for getting out and exploring places you ordinarily wouldn’t discover on your own. I can’t tell you how many times I went off in search of a cache and have been rewarded with the journey to it.
See this image of geocaching and more on my photography website.