Every Solution needs a Problem. I bought a small, waterproof GPS unit, and decided to try some geocaching.After the usual new-gizmo frustration, I managed to find a website & download a cache.
I found this after some more slightly comical learning-curve stuff.
It was well-packed. The trash bag was a nice idea. I didn't see any trash on the trail, so I took the bag to place in the next cache I visit.