I had heard about geocaching from a few friends before I had a smart phone. The idea was intriguing, and thought it would be a good activity when my kids got a little older. Then one day, we were in the park and one of my kids came up to me convinced he had found pirates treasure. Immediately, I had recognized what it was, and shared his excitement.
I downloaded the app, created a free account and helped explain what it was and how you do it.