Has anyone gotten into this? I just learned about it a few months back. Someone with a GPS unit that comes on our hikes has been helping us find them whenever our hike takes us near a site. Yesterday we found the one at Bear Swamp Hill. There are several at Wells Mills, where I work, and we didn't even know about it until we found them on the website. It seems like a pretty neat hobby. Now if I only had a GPS unit. The prices are coming down, so I might be able to get one for our park.