This is pretty freakin' cool. I checked out the site and went to the map of my area and there's cache's hidden all over the place. Really cool. Just might take the boys on a little geocaching this weekend. Thanks for the link!
I have done it a few times. After I left active duty I was unemployed for a few months and did it then. Now I have 2 little kids and NO TIME, but I do like Geocaching. I even started making a huge hunt that would take place throughout the largest park in Seattle. It would have taken probably 2 days to do it. But I got a job and then moved away from the park and never finished.