Geocaching is hide & seek with a GPS. Your grandkids may be more familiar with the tech requirements than you are, but it’s huge family fun. There are a million sites around the world any day of the week. Don’t call it a treasure hunt. What you’ll find are trinkets and geegaws. They’re not meant to taken away (not that you’d want to). You simply sign a logbook at the site and go on your way.And just like all the coolest things on the internet, it’s still free.