On April 22nd, 1970, millions of Americans took to the nation's streets in protest. They weren't marching against the war in Vietnam or in support of civil rights. Instead, they had turned out to protest the damage being done to the environment by pollution. Thirty-eight years later, the celebration of Earth Day ? now observed annually in countries around the world ? has matured to include more than protest. Many of this year's Earth Day events focus on simply enjoying what nature has to offer. Mike Osborne attended one such Earth Day-inspired event this past weekend in Kentucky.

Kentucky State Parks Ranger and Naturalist Robert Myers has a difficult job. In an increasingly sedentary, technology obsessed culture, it's his task to tempt people away from the TV and computer. "A lot of people are not going outdoors," he points out. "They're spending more time on computers and things like that. We needed people to use that technology, but also enjoy the public lands that Kentucky has to offer."

Rather than fight technology, Ranger Myers found a way to embrace it. This past weekend, Myers held his third annual Geocaching Weekend at Kentucky's Cumberland and Dale Hollow Lake State Parks.

Geocaching is high-tech treasure hunting. "We all loved scavenger hunts when we were kids. This is the adult version," says Myers. "We've got our little electronic toys and we've got our competitive spirit and we wanna go find that cache!"

More importantly, though, the competition gets people outdoors and into the parks. "It gets you on the trails, it gets you out of your car, and [you] see just how beautiful the park is right now. We have various wild flowers blooming, the trees are finally leafing out, and we're getting rid of that wintertime blahs, and it's just a great event all around."

The electronic toys Myers refers to are GPS or Global Positioning System receivers. These radio navigation devices are about the size of a cell phone and can pinpoint your location within three meters, anywhere on the planet.

Armed with latitude and longitude coordinates supplied by Ranger Myers and their GPS device, Glen Girdler and Taylor Johnson have already found their first cache. But It wasn't as easy as it might sound. GPS units are only accurate to within a few meters, and to make the hunt more interesting, the caches are never left in plain sight. They're all carefully hidden.

This cache was a small plastic tube placed in an abandoned bird's nest on a tree branch just over their heads. Even with the GPS unit, and written clues supplied by Ranger Myers, it took the couple about ten minutes to find this first of 42 caches placed throughout the park for the event. They log their find and move on to the next quest.

The night before the hunt began, I had a chance to sit down with three veteran hunters. They all insisted on using their geocache monikers. These are the names they use in the online communities where geocaching finds are logged and discussed.

Turtle Greg notes that geocaching is the incentive he needs to get outdoors and get some exercise. "A lot of times I'll be completely wore out and I'll say 'I just can't go anymore.' And there will be one more cache and that cache will be what gets me over that hump." He compares his motivation to the challenge that drives mountain climbers. "A lot of people say, ''Well I climb it because it's there.' I need more than that, 'cause it's there.' You tell me there's a cache on top of that mountain, I'm climbing it!"

Lumberjack Tom notes that carrying a GPS device allows him to know where he is all the time and that gives him the confidence to enjoy wilderness areas he might otherwise find intimidating. "Your heart always steps up a beat or two when you start losing sight of some of your recognizable features, but with a GPS-R [GPS receiver] you can go just about anywhere. So it makes it fun to venture out."

A geocacher using the name Smee says that cost or fear of the technology shouldn't keep anyone from exploring the world, one cache at a time. "Minimal technology, minimal cost." She admits that there is an initial outlay for the GPS receiver, "but beyond that you put on a pair of boots and you go. And I think that's pretty cool."

Of course, it is possible to get a little too close to nature. At last year's Lake Cumberland Geocache Weekend, a couple of hunters discovered a poisonous snake curled up next to one of the caches, a danger Ranger Myers warned this year's participants about in his opening instructions. "Always watch where you grab and always watch what you walk over."

And he had some advice for those who didn't like wandering around in the woods. "There's a lot of cities that have urban caches if you're not into the outdoors. The best thing about it is that it's a sport for people that like all different things."

That wide appeal is evident in the sport's rapid expansion. In just eight years it's grown from a single cache planted in the U.S. state of Oregon, to an estimated 600,000 caches in more than 100 countries.

Lumberjack Tom has logged more than 6000 finds. That still doesn't put him in the top ranks of the sport, but it does make him pretty compulsive about the sport. He once wrote a poem for his wife, apologizing for geocaching's addictive qualities. "If I weren't so cache consumed and otherwise addicted, my thoughts of you would have more room and not be so conflicted. I hope you'll never doubt my love. It's as bright as the brightest star. That said, 'I'm sorry for the shove, but I must get to the car!'" he concludes with a laugh.

If you'd like to learn more about geocaching, there are several websites devoted to the sport. The largest is geocaching.com.