Geocaching is a high-tech treasure hunt. People, and it can be anybody pretty much anywhere, hide things and post the coordinates on a website. Cachers take the coordinates and any hints or description given and go find the cache. They then sign the logbook, perhaps trade for something in the container, and leave it for the next person to enjoy finding.
For more details, go to geocaching.com.
This is something I always wanted to do, I am headed there right now! By the way, I was born in Hollister, my uncle ranched out on the New IdrIa Rd and I am still madly in love with Tres Pinos, Paicines, New Idria, Bolado Park, the Pinnacles and everything about San Benito County. Glad you enjoyed your trip, finishing up near my current home away from home, Morro Bay!