Geocaching involves finding a hidden container by the use of a hand-held GPS device. There are many thousand of them all over the country. There are over 330,000 throughout the world, according the the site I've linked to near the bottom of this page.
The picture above was taken at a geocache site in Hopedale on November 10, 2006. Geocachers finding the cache can leave an item and take an item. It seems that people often leave more than they take, as you can tell by the amount of "stuff" in the picture. (Before I left, I put all the stuff back into the plastic bottle that you can see at the left side of the picture. Then I put the bottle a little bit out of sight, just as I had found it a few minutes earlier.))
To get started, first you need a GPS device and Internet access. Okay, looks like you have Internet access. The GPS costs about $100. You'll also need a cable to connect the GPS to the computer. (If you like the idea of geocaching, but don't want to spend $100+, skip down to the last paragraph for a similar but cheaper activity.)
The geocaching website will explain the activity better than I can, but I'll give you a little more. I've never gone through the whole process by myself. It's my son who does that, but I've gone along with him at least a few dozen times. He usually starts by downloading all the geocache sites within ten miles of where he'll be located. When he's here, he'll get those in the Hopedale area. We'll decide on one and then drive to the area. You can usually drive to within about a mile of the cache. The next step is to get out of the car and walk. Since the cache coordinates have been downloaded into the GPS, it gives you the direction to walk (arrow in display) and the distance. The GPS is usually good enough to get you within about twenty to fifty feet of the cache. Then you have to hunt around. The cache will usually be hidden under sticks, a stump, a rock, leaves, or a combination of these and other items. When you find it, you open it and take a look at what's in there. There will be a little pad and a pen for you to sign, along with perhaps a sentence about the weather, your ease or difficulty in finding the cache, whatever. When you get home, you can record your finding in your account on the geocaching website.
One thing I like about geocaching is that it gets you into interesting areas you wouldn't know about otherwise. The cache pictured above is in the Parklands. Many of the people who have found it have never been there before. I've been to quite a few neat locations I wouldn't have guessed existed if it weren't for geocaching. If you're interested in getting into this and need more information, you could email me. (Link on homepage) If I can't help, I'll pass you on to my son who'll probably be able to answer your questions. However, you can probably find what you need to know at www.geocaching.com/ I just took a look at the site and searched for caches in the 01747 ZIP area. It listed 147, of which 26 were no more than five miles away.
Now if you like the idea of geocaching, but you don't want to run out and spend $100 on a GPS, here's an alternative. Thanks to Leigh Allen for mentioning this to me. It's called letterboxing. You can find all you need to know about it at letterboxing.org.