I am currently teaching a Highly Abled group of students (used to be "Gifted and Talented") in grades 3-6 and have been using a course in "Instrumental Enrichment" by Reuven Feuerstein called Orientation in Space II. It follows up OIS I which deals with understanding internal space and relating to things around us (front, back, left, and right). OIS II deals with understanding space in relation to the compass points. This was a natural for introducing Geocaching. I am having the students develop three different caches that we will place in the community where our school is located.
They certainly enjoyed when we went to find a nearby cache someone else had placed.