Geocaching!

A marvelous game of hide-and-seek, "geocaching" is a hobby where people use gps devices to conceal and locate 'caches'--generally small, waterproof containers that contain a logbook, and often little trinkets or toys. Players can make them out of any sort of container and put anything they want in them. Once they hide one, they report it on the geocaching website, where other people can locate and go in search of them. Some are pretty easy to find while others require long hikes, climbing up trees, or even diving underwater to find. There are understood rules of conduct to take part in geocaching, one of which is if you take something from a cache you must leave something else behind. If a cache is vandalized or stolen, it is said to have been "muggled" or "plundered." A modern take on the 150-year-old game of letterboxing, geocaching is played in over 100 countries and on all seven continents. As of this writing, there are over a million active geocaches in activity. There are all sorts of fun things involved such as "travel bugs," which are plastic figurines sporting a PIN-embedded tag, that are moved from cache to cache by geocaching participants who log their travels. "Geocoins" are similar objects, often engraved with tracking numbers as well as a symbol or design representing a certain geocacher's handle. Some caches involve a series of multiple discoveries, some are meant to be found at night by way of reflectors, some you have to solve a puzzle or code to find, and some are meant to be taken once found and hidden somewhere else by the latest finder.
I went in search for the first time today in the desert around my town. I had no luck, but I think I was searching for one too hard for a newbie. I did meet a stranger, however, who gave me some clues and a pointy walking stick in case of snakes ^_^