Link Directory: Outdoor Activities
- Benchmarking: Use your GPS unit to seek out NGS survey markers and other locations that have been marked in the U.S.
- Cistes: Find a box full of trinkets using clues/directions (not a gps)
- Earthcaching: "The EarthCache program is a subset of geocaching in which the "treasure" a cacher finds is not a physical container with trinkets, but an educational lesson of the Earth."
- EcoScavenger: This is the official web site for excursions similar to letterboxing and geocaching, but where the destination is the cache.
- Geocaching: The main geocaching website--letterboxing with a GPS, kind of, but not quite
- Geodashing: "Players use GPS receivers on a playing field that covers the entire planet. The waypoints, or dashpoints, to be reached are randomly selected. The win goes to the team that reaches the most dashpoints in a given time."
- Highpointers: The goal: Visit the highest point in each of the 50 states of America. This is their website....
- Markeroni: "Snarfing" (visiting & taking photographs of) Historical Markers, Plaques, etc all over the world
- Terracaching: Another geocaching database - organized differently from geocaching.com
- the Degree Confluence Project: The goal of the project is to visit each of the latitude and longitude integer degree intersections in the world, take photos at each location, and with the pictures and stories told here
- Valley Quest: "Questing is a place-based education model of creating and exchanging treasure hunts in order to collect and share your community's distinct natural and cultural heritage"
- Waymarking: Travellers catalog, mark, locate and log unique and interesting objects, sights and locations around the world.