And what is the best way to get started?
The basic idea is:
Someone hides a box, which can range from an Altoids tin to a big tupperware thing, at a certain location. Then that someone posts the GPS coordinates of the box to one of the many geocaching lists/groups. Then people go and look for it. Usually, there are various trinkets in the box; if you find it, you’re supposed to leave one thing (which may be a score from a previous cache) and take one thing if you wish. Lots of them also have a notebook where you can leave a note and the date/time of the find.
Some are puzzles where you have to deduce the lat/long from other clues. And some are “chained” where the contents of one box are the coordinates or clue to the next box, etc.
All this is second-hand from my friend the geocache addict, BTW. I’ve never tried it myself.
What is geocaching?
Basically, a good excuse for geeks to get out and get some exercise. It’s a lot of fun.
Geeks using a billion dollar satellite positioning system to find tupperware in the woods.
True! And it’s fun! We just found our first geocache on fourth of July. I used the iPhone geocache app to do it. It was a blast.
Once you find the cache you write in the log book. You can log it found online as well. Some of the caches have little trinkets that you can take, as long as you leave a little trinket behind. Be sure to put it back exactly where you find it! Some have “trackable items” that have codes on them. You take one and leave it at another cache. You record the log online and you can see how far it’s traveled.
Letterboxing is a low tech version- uses clues rather than coordinates. Letterboxing.com has them sorted by region and you can print out the clues.
I think geocaching.com is the biggest site, with the most caches. Geocaching is great way to discover nice little nooks and crannies, like parks or lookouts, that you never knew existed in your local area. When we travel, I look up the caches where we are going, since people tend to put them in interesting places.
It’s referred to as a high-tech treasure hunt and it’s a lot of fun. I don’t like hiking—too pointless. But geocaching gives you a reason to do it. Although, actually, there are so many different levels and types of geocaching that you could do it just staying in your car, no hiking involved. I prefer to do it in the fall and winter when it’s not so hot and there are fewer snakes around.
That’s what it is for me. I somewhat enjoy hiking, but haven’t had much motivation to do it in years. For several months, geocaching has been giving me not only a reason but a goal. Not only that but I’ve seen many things I wouldn’t have otherwise seen, like cemetaries from the 19th century and city monuments. I especially like the ones that involve some hiking, but there are also ones you can park right beside, called “park and grabs”.
All you need to get started really is a half-decent GPS receiver and a pen. You find the coordinates listed on the website which will take you within about 30 feet and then it’s a matter of finding the thing. And they’re all over the place too. There are at least two in Barrow, Alaska. So at least within the United States (there are some all over the world but I don’t know of the frequency in other countries), you’re almost definitely close to several of them.
This statement should be on a T-shirt.
It’s a great way to lure my next victi…uh…er…
runs away
Geocaching.com is a good place to start. A lot of folks also go to Terracaching.com, which is the same concept, but the caches are more puzzle and challenge oriented. Also Geocaching no longer allows virtual caches, whereas Terracaching does. With a virtual , there is no physical cache container. The object is to send someone to a site that is out of the ordinary where you can’t hide a container. You tell them to find something, like a date on a marker, and use that for the confirmation code.
Here’s an example of a virtual cache. For obvious reasons, it would not be cool to have people climbing around Hoover Dam looking for an ammo can. 
Definitely. A few years ago I found a nice secluded spot to place my own cache, and after planting it, I logged onto the website at home to log it. I got an email telling me that I’d placed mine too close to another cache, and needed to move it. When I hiked out to move it the next day, I found that I’d placed my cache ten feet away from the other cache.
I am waiting for the first serial killer to start geocaching where “his” hookers are.
http://forums.groundspeak.com/GC/
Read the Getting Started forum to see what it takes, and look through the GPS and Technology forum for info about which units are popular with geocachers. When you are choosing a GPS unit, be aware that most of them designed for cars are not suitable for geocaching.