All you need to play is a GPS (and a membership). Plug in the coordinates of the Geocache you are hunting for and head in that direction. There are plenty Caches to choose from, so if you’re a beginner you can look for Caches in the park, when you’ve built your skills you can search in the woods, and when you are an expert you can trail blaze through the mountains.
The GPS will only get you so far. Once you are reach the coordinates of your destination, it is up to you to find the Cache. The Caches can be hidden in plain sight or very cleverly; for example, one girl carved a hole in a log, stuck a Geocache inside, attached a swinging door to cover it, and turned the log door-side-down to look like part of the scenery. Level: expert.
Some Geocaches include log books so that all of the successful treasure hunters can sign in, while others include actual treasures that you can take with you, and in return you are expected to leave something of equal or greater value behind for the next treasure hunter. When you get home you can sign in to the Geocaching website to log your adventure for the rest of the world to read about.
Instant adventure! Geocaching is definitely on my to-do list.