According to Wikipedia: "Geocaching is an outdoor activity in which the participants use a Global Positioning System (GPS) receiver or other navigational techniques to hide and seek containers, called "geocaches" or "caches", anywhere in the world. A typical cache is a small waterproof container containing a logbook. Larger containers such as plastic storage containers (tupperware or similar) or ammo boxes can also contain items for trading, usually toys or trinkets of little value. Geocaching is most often described as a "game of high-tech hide and seek," sharing many aspects with benchmarking, trigpointing, orienteering, treasure-hunting, Letterboxing, and waymarking."

When you find the sketching point of a Group of Seven painting, Write the first entry in a log book, put it in a zip-lock bag under a cairn (pile of rocks) and note the GPS co-ordinates. Then just post the co-ordinates.