ALBANY - Before he discovered geocaching in 2008, Wayne Stemple spent his free time on the couch or playing with his computer.

Now the Albany resident is outdoors every chance he can get, using a handheld global-positioning system (GPS) to guide him to the coordinates of hidden "caches" in all terrains, rural and urban.

His geocaching conquests have led him to the top of a tree, down busy city streets, to the top of a New Jersey mountain, off trails into gnarly underbrush and into cemeteries to decode clues hidden in tombstone inscriptions.

Geocaching unites the best of modern geekery with good old-fashioned treasure hunting. Geocachers hide containers, ranging from pea-sized canisters to 20-liter buckets or larger, and post the location coordinates on geocaching.com so others can find them. The typical cache is a Tupperware container or ammo box and contains a notebook for logging visits, small prizes to trade, or dog tags called "travel bugs" that geocachers move from cache to cache and track online.

"The travel bugs, you kind of live vicariously through them," Stemple said. Geocaches he hid in coordination with the Green County Barn Quilt series recently won a "series of the month" award from the Wisconsin Geocaching Association.

This summer, the City of Monroe Parks and Rec Department is coordinating geocaches downtown with Main Street Monroe's summer-long Pirates on the Square series.

In preparation, Dan Bestul is leading a free introductory class on geocaching at 6:30 p.m. Wednesday, May 30 at the Monroe Community Center and taking the class out on a practice geocaching mission.

Bestul, a family law attorney by day, first got into geocaching about eight years ago. He's an assistant Scoutmaster for Boy Scouts Troop 180, and at the time was preparing the troop for a backpacking trip in New Mexico. He'd been instructed to help navigate the boys through the trip using as much GPS as possible.

That's when he came across geocaching.

Geocaching as a sport was only a few years old back then. In 2000, President Clinton lifted limits on the availability of GPS data to the general population. Suddenly, ordinary people had access to vastly more precise positioning information, and within weeks, self-proclaimed geeks everywhere were devising ways to have fun with this data via geocaching.

High-tech skills are not necessary to geocache. All you need to get started is a GPS unit or a free-to-download geocaching app on a smartphone. Beyond that, geocaching just takes sweat, patience and a little ingenuity.

Geocaching.com currently lists almost 2 million active geocaches worldwide and more than 5 million registered geocachers.

Like any subculture, geocaching has its own language and inside jokes. A non-geocacher is referred to as "muggle," a term lifted from the Harry Potter book series that means a person lacking magical abilities.

"You don't want muggles to find your geocaches," joked Bestul, who's searched for geocaches in Alaska, in Oz Park in Chicago, in Monterey, Calif., and inside a public sculpture in Naperville, Ill.

"There's one within a block and a half of here," he said, gesturing toward the Courthouse Square from his law office in downtown Monroe. In all, he says he's logged about 100 geocache finds.

When Stemple first started geocaching four years ago, there were maybe a dozen geocaches in all of Green County. Now he counts about 175, many of them his own.

Stemple works as a senior software developer for an insurance company in Madison, but you wouldn't know it when he's out geocaching in camouflage pants and hiking boots, dodging thorns in a thicket of bushes off the trails in the Albany Wildlife Area to locate one of his caches, a ceramic rabbit called "Wabbit Twacks."

"It's an out for me. I'm a white-collar worker," he said. "This is the other side of the emotional, psychological coin. It's a way to kick back. It's a great way for couch potatoes to get off the couch."

Just this year, at the age of 57, he bought his first mountain bike - to help him geocache.

Late one Fourth of July, after finishing up his side job running a fireworks show in Milwaukee, he decided to stay up all night and search for geocaches around the city and in Waukesha. He fueled up on potato salad and set out in his car. He was still out hunting at 3 a.m., when he had to watch out for the bread trucks that were starting their morning rounds and barreling out of alleys "on two wheels."

When the sun came up, he drove home.

Geocaching isn't necessarily a solitary adventure. Bestul goes out with his wife or his Scouts. Stemple takes his 8-year-old grandson geocaching.

It's also a good way to meet people. One day Stemple was tracking the alerts popping up on geocaching.com for caches near his house in Albany when he realized the geocachers, a couple from Machesney Park, Ill., were probably right across the street at that very moment. So he walked out the front door and caught up with them: "Oh, you must be Jen and Brutus!

"And we've been friends ever since then," he said.

Geocachers seek each other out in other ways, too. Enthusiasts from around the country will be gathering in West Bend in mid-August for the "West Bend $1,000 Cache Ba$h," a weekend-long "geocaching mega-event." (More info is at westbendgeocaching.com.)

Ultimately, the goal of geocaching isn't the cache but the journey to find it. Geocachers often hide their containers in areas they want others to experience: an overlook with a pretty view, a little-trafficked area in a state park.

"It takes you to neat places. That's kind of the idea," Bestul said.