I just got into this, and thought I should share it with all you guys/gals.
Geocaching is an entertaining adventure game for gps users. Participating in a cache hunt is a good way to take advantage of the wonderful features and capability of a gps unit. The basic idea is to have individuals and organizations set up caches all over the world and share the locations of these caches on the internet. GPS users can then use the location coordinates to find the caches. Once found, a cache may provide the visitor with a wide variety of rewards. All the visitor is asked to do is if they get something they should try to leave something for the cache.
What is usually in a cache?
A cache can come in many forms but the first item should always be the logbook. In its simplest form a cache can be just a logbook and nothing else. The logbook contains information from the founder of the cache and notes from the cache's visitors. The logbook can contain much valuable, rewarding, and entertaining information. A logbook might contain information about nearby attractions, coordinates to other unpublished caches, and even jokes written by visitors. If you get some information from a logbook you should give some back. At the very least you can leave the date and time you visited the cache.
Larger caches may consist of a waterproof plastic bucket placed tastefully within the local terrain. The bucket will contain the logbook and any number of more or less valuable items. These items turn the cache into a true treasure hunt. You never know what the founder or other visitors of the cache may have left there for you to enjoy. Remember, if you take something, its only fair for you to leave something in return. Items in a bucket cache could be: Maps, books, software, hardware, CD's, videos, pictures, money, jewelry, tickets, antiques, tools, games, etc. It is recommended that items in a bucket cache be individually packaged in a clear zipped plastic bag to protect them.
Anyway I love it, I've found 9 cache's so far. Here is the link.
It's free, it's fun, and you can get some cool things in the process.