“It’s a great family sport,” Anderson said. He wants to expand his geo-kids into a family geocaching club.

Mike Omtvedt of Madison Lake started geocaching about five years ago when he “was looking for something different to do with his kids.” A friend introduced him to the sport.

Now Omtvedt teaches Boy Scouts how to use GPS handheld units in orienteering. “We use geocaching as a way for scouts to practice their skills,” he said.

“Probably the great value of geocaching is getting kids outdoors, steering them away from computers,” Omtvedt said.

Most geocaches involve a hike, usually in a park. The idea is that getting to the cache should be as enjoyable and rewarding as finding the cache.

Until two years ago the Minnesota Department of Natural Resources did not allow caches to be hidden in state parks. Now they can, but with restrictions posted on the DNR’s Web site. Minnesota has almost 6,000 caches.

Most Minnesota geocachers have found caches posted by King Boreas, who has hidden more than 1,500 caches with several in the Mankato area.

Tomslusher, which is a geocacher handle, is another well-known geocacher in this area. “He has a dandy puzzle to figure out the coordinates using wristwatches and sun dials,” Anderson said.

Being the first to find (FTF) a cache receives special recognition. “Ramsey63 was the first to find all of the geocatches we’ve hidden,” Anderson said.

Nanocaches are less than a half inch, with only a tiny logbook. “I found one, a magnetic thing, that was painted red and attached to a stop sign,” Geary said. Other sizes range from microcaches, usually a film canister, to larger ones up to 4 feet tall, such as ammunition boxes.

Variations on the game include Webcam caches. The idea is to get yourself in front of the camera to log your visit. Geary found one in Grand Rapids, called his sister in Hawaii who went to the Webcam’s computer site, and took a picture him on her monitor. “Then you publish the picture to prove you were there,” Geary said.

Some caches called “multis” link a series of coordinates with clues to reach a final destination. “There is a new one at Minneopa Falls,” Geary said.

A virtual cache is one where the seekers must answer a question from a landmark to verify they were physically at the location. The sign noting the high water mark of a flood in Seven Mile Creek between Mankato and St. Peter is a clue in one virtual cache, Geary said.

Geocaching even has its own lingo. Posts include references to Muggles (non-geocachers, just like nonmagical people in Harry Potter books), hitchhikers (travel bugs) and a number of acronyms.

The popularity of geocaching has grown rapidly since it began May 3, 2000, when Dave Ulmer hid a can of beans and other treasures near Portland, Ore., to test the GPS signals the government had just opened to the public. There are now almost a half million caches hidden in 222 countries.