If you don't know how to Geocache, it's a simple, really fun thing to do. Geocaching (gee-oh-cashing) is a real-life treasure hunt. The "treasure," items placed in a geocache container by other geocachers, can be located anywhere on the planet. You can search and find geocaches using specific GPS coordinates that direct you to each location.
Placing new geocaches is part of the fun. Simply hide a geocache container in the location of your choice, and pinpoint it's GPS location online at the Geocache website. That's it! Anyone with a GPS unit can participate. Sign-up for a free membership at geocache.com.
This video provides a simple explanation:
Geocaching around the San Juan Islands Washington:
1. Sign up for a free membership.
2. Select "Hide & Seek a Cache."
3. Enter '98250' in the zip code field and click "search."
4. Browse the geocaches on the list and select the one you want.
5. Enter the geocache coordinates into your GPS Device.
6. Follow the coordinates to the hidden geocache and sign the logbook. Bring along interesting items to leave in the container, as well. Bring your camera and document your find!