Treasure hunting

Matt and the boys have been treasure hunting and I decided to join them this afternoon.  I think it is called Geo-caching. It is similar to letterboxing.  These little boxes are hidden all over the world and we just follow the directions on Matt's iphone with clues and search them out.  They contain little treasures that previous 'finders' have left and a notebook that you sign your name and date in.  You are allowed to choose something from the container as long as you leave something for the next treasure hunter.  Some contain a geo-coin thingy and you have to register this coin online so it can be tracked and choose a new location to hide it in.  One coin we found today started in the Netherlands!  I think we found 4 today!