Geocaching is an activity where you use your Global Positioning System (GPS) to find "things" other people have hidden. Those "things" are called "caches" or "geocaches". They are usually rubbermaid containers, ammo cans and even things as small as match stick cases. They normally contain a log book and several trinkets.
When people hide a geocache, they save the GPS coordinates (longitude and latitude) and then post them on http://www.geocaching.com/. Other people can then go on http://www.geocaching.com/ and get those coordinates (also known as waypoints) and load them into their GPS. Then, they go out into the world and try to find them.
Berkshire County is LOADED with Geocaches. See the map below.
Many caches are hidden in interesting places, like near nice waterfalls, cliffs, historic locations, etc... so get out your GPS and go discover the best the Berkshires (and the world) has to offer!
Check out this video on a Geocache on one I was the First person To Find (FTF):
Check out this video on a Geocache I created up in Vermont
In addition to the normal little trinkets, caches can contain special trinkets called travel bugs. These are small stuffed animals other other things that usually have a mission, like go visit Canada, cross the State, meet new friends etc... People will move a travel bug from one geocache to another when they find one. Travel bugs have a special tag with a number on them. You need to log this number into www.geocaching.com when you move the travel bug from one location to another. If you happen to find a travel bug and move it to another cache all in the same trip, make sure you get this number or you'll have to go back to the cache to get it later. (Happened to me once!)
I use a program named Expert GPS to download waypoints from geocaching.com and load them into my GPS. I also use it for making maps. You can also use Easy GPS (which is free) to do pretty much the same thing as Expert GPS, except you don't get to see the topo map like shown above. Prior to discovering Expert GPS and Easy GPS, I used to enter the coordinates into my GPS manually. If you don't know how to do that, you can just write the coordinates down and use your GPS to walk to them.
Normally, your GPS will get you within 20 or 30 feet of the cache, but you willl have to look around under logs, rocks, sticks, etc.. to find them. Many caches are easy to find because people pile up a bunch of sticks all facing the same direction. Really good caches are hidden in natural crevaces or holes where it's not so obvious.
Please see http://www.berkshiresports.org/index.php?ID=gpsgeocaching for a guide to GPS units. Even the most basic GPS unit is good enough to use for geocaching, but I highly recommend buying the Garmin GPSMap 60CSx or Garmin GPSMap 60Cx.