Geocaching is a fun thing to do that gets us out of the house....there are geocaches pretty much everywhere, and looking for and then finding them adds a new element to a bike ride or walk.....the kids get very excited looking for them.....usually you start on line and identify one or two in an area where we will be headed....they give hints as to where they are that help you find them....once close, you use the GPS in your phone to zero in.....even at that you end up having to search.......it ends up a little.like hide and seek. Find an easy one near home and try it.
There are a number of geocaching apps....you download to your phone.....many are free....if you pay extra....you get more information and services....but you don't need to.
We used c:geo and one called geocaching.com
en.m.wikipedia.org/w iki/Geocaching