Geocaching according to Wikipedia:
Geocaching is an outdoor recreational activity, in which the participants use a GPS receiver or mobile device and other navigational techniques to hide and seek containers, called "geocaches" or "caches", anywhere in the world.
I heard about it quite a long time ago and I always thought it sounded like a ton of fun. Yesterday, randomly remembering, I decided to actually try it with a friend of mine named Avi.
The Premise
I'm not expert by any stretch on Geocaching (obviously, considering I only started yesterday), but here is how Geocaching works in a nutshell:
Someone, somewhere, decides to hide a "cache", which is basically a container of some sort. He or she places some items inside if he or she would so desire, and also includes a logbook and a pen. They add the coordinates of the cache to the worldwide database, and then other people can find that cache.
With me so far?
Should you decide to join the great game, you download the app to get coordinates of the caches nearby, and go looking for them with your iPhone's GPS as your aid.
When you find one, you add your name and the date to the logbook, and can go back and see how many other people have discovered said cache. Often there is some sort of swag in the cache (toy cars, stuffed animals, etc.) and the general rule is you can take something as long as you replace it with something else of your own.
Oh, and yes, this all means that there is a constant, continuous treasure hunt of sorts going on all around the world, all the time. You probably had no idea, but I bet there are hundreds of caches near where you live, all within ten minutes of driving. You probably even pass by many of them everyday. Pretty cool, eh?
The Intro App
Should you, like me, decide one day you just want to give Geocaching a shot, there is a whole official website for it, but you really need the iPhone app that uses your GPS data to track you if you actually want to be able to find any of the caches. There are two official iPhone apps (and from what I've seen, I wouldn't go near any of the other ones): There is the introductory app, and then there is the full-on app. The former is free, the latter costs $10.

For our pilgrimage yesterday, I decided to start out with just the free introductory app. It lets you see the nearest three caches, and while it isn't updated for Retina screens, nor the iPhone 5, all other necessary features were there. We got the coordinates to the nearest cache and were on our way in no time.
Our First Cache
We drove around for a few minutes until the GPS said we were real close. We found the closest parking we could, and walked the rest of the way. The cache, from the looks of it, was hidden in a small little park a few minutes from my house. It's not a park that I frequent at all, but I certainly knew about it.
By the time we had set foot on the park grounds itself, the app had congratulated us on being really close to the cache. I switched the app to the compass mode, and we started our search.
We had a bit of trouble with using the app at first. We had no clue what we were doing, and the app, with astonishing accuracy, seemed as if it was playing a game of Hot and Cold with us. The number of feet we were away from the cache kept on rapidly switching from only about 20, to way up to 60 as we walked around.
Finally, we were able to pinpoint the little bit of foliage in which we were sure the cache was hidden. With the help of the cache's hint (also displayed in the app) we knew that it was next to a fallen tree. There were a lot of little fallen trees in the area, though. With a bit of rummaging around, mostly on Avi's part, we finally found the cache.

It was a rectangular metal box with a hinged closing mechanism. We pried it open and took a look at what was inside. Needless to say, we were both pretty excited. We were freakin' treasure hunters for a few seconds.
Inside was the expected logbook in which I accounted for out little visit — there were at least about 50 other people who had signed as well. I also marked the cache as found within the app. There were a few toy cars inside as well, along with some pens, stickers, and some Barbie thing. We took a toy car, and Avi replaced it with the blade of a hockey stick.

We immediately agreed that we wanted to find another one. We got the location for the next closest one, and headed over there. Just as with the first, we were able to get the approximate location via the app, but it still required rummaging to actually find. Again, mostly by Avi (I really didn't want to risk getting Poison Ivy — not fun — but Avi never seemed to be allergic like I am).
The second cache we found was considerable larger than the first with quite a few stuffed animals, and even more toy cars.
Both were considered by the app to be easy to find.
$10 For More Than That In Fun/Adventure
I called this post our first adventure because it definitely is only our first. I can't wait to go back out again. It was a ton of fun, even with the slight awkwardness of passersby having no clue what the hell we were doing.
If you've got some free time on a weekend, this is a great thing to do with friends. Highly recommended. Really. You know it sounds like fun — now get out there and actually do it!
Oh, and I bought the full $10 Geocaching app.