Although I'm much more likely to spend a lovely summer day with my butt glued to the chair working on a new TUAW post, I do enjoy the sport/hobby/game of geocaching. If you're not familiar with the term, geocaching is defined as "a global treasure hunting game where participants locate hidden physical containers, called geocaches, outdoors and then share their experience online." When I first started geocaching, smartphones didn't exist so I'd print out a map, grab my Garmin GPS, and head out to the field. For the last few years, there has been a boom in iPhone apps for geocaching. Here are five apps to help you enjoy finding those hidden caches.
Geocaching Intro (Free)
GroundSpeak is the company that runs the Geocaching.com website, the world's largest repository of geocache location information with over 1,450,000 active caches listed. As a for-profit organization, Groundspeak has a vested interest in getting new members into the hobby. The app is a way to get you hooked on geocaching by letting you find three geocaches near your current location, provide you with the requisite coordinates, hints, and description, and help you navigate to the cache. A bonus is that the app alerts you when you're getting close to the cache location by vibrating and making a sound. It's a wonderful and free app for deciding whether or not geocaching captures your attention.
If that free intro got you hooked, you may want to graduate to a Geocaching.com premium account so that you get access to some special caches and features that aren't open to the general public. The official Geocaching app was the first caching app for the iPhone, and it has improved over the years to become the tool for finding and reporting caches.
The feature set is incredible. Over a 3G data connection you can pick up information about any of the caches worldwide, log your finds, save listings for offline use (helpful in backcountry caching), navigate to caches with a compass arrow, browse photo galleries and cache attributes, and more. You'll even know if you've been to a cache before or if a cache is currently inactive.
Since I've had this app, I haven't had to print out maps and I sold my old Garmin GPS. The app and iPhone work great together, although you'll probably want to have an external battery pack on hand while caching.