It started innocently enough with a school project for one of the kids.

From there, Terry and Natalie Bergenuin began learning more and more about the pre-1840 "mountain men" of the West and soon fell in love with the era.Before long they were spending their weekends at "rendezvous" much like the one held at Fort Buenaventura State Park over the weekend that drew thousands of people decked out in buckskin and linen.

Rangers estimated there were 250 campsites at the park.

"This is our most favorite thing to do in the whole world," said Natalie Bergenuin. She was dressed in a soft, handmade elk-skin dress with intricate bead jewelry, as she surveyed children Christopher, 14; Heather, 18; and Melanie, 20. Another son, Matthew, 12, was off trying to land some treats shot from a candy cannon.

The mountain man hobby is a way of life for many people who form lifelong friendships with people from all parts of the country as they rough it, in varying degrees, at these rendezvous that are scheduled almost every weekend in warm weather.

The rendezvous offer modern-day types the chance to dress, eat, camp and take part in activities that were common to the old-time mountaineers. They also can buy or sell craft items.

There are contests to see who can dress or camp most authentically, there is a frying pan toss competition, Dutch oven cooking contest, and knife and tomahawk throwing events. Canoe races and wagon rides also are popular.

People even have rendezvous names. For example, Natalie Bergenuin is "Grandmother Grizzly" while her husband is "Black-heart."

In real life, she's the assistant postmaster in Moreland, Idaho. Terry Bergenuin works for the Idaho National Engineering and Environmental Laboratory.

The Bergenuins see this as a healthy family activity that satisfies everyone's interest in history and still offers something for each individual.

Terry Bergenuin is keen on muzzle-loading, black-powder rifles. Son Christopher is determined to win canoe races. The women in the family love the artifacts and beautiful Indian jewelry.

Everyone in their family dresses in period clothes and they enjoy making things from that era, like the candle-filled cedar lantern Terry Bergenuin crafted.

The family tried camping in tents at first, but that got really uncomfortable, especially after Dad had back surgery and Mom needed some modern amenities for her health. So they're happy to park their well-stocked Winnebago in the "tin tepee" part of the rendezvous camp.

Not so for Todd "Teton Todd" Glover of Riverton, who's keen on authenticity and estimates he spends about 10 hours a week during the winter off-rendezvous season researching original journals, history books and museums along with making nearly everything he wears or carries.

"I have just had a love of history since I was little," Glover said. "I don't shoot as much as I did, but I do a lot of tanning and quilling (using porcupine quills to decorate items such as hatbands).

Glover, a full-time member of the National Guard, made his own black-powder rifle, sewed his linen clothes, fashioned his powder horn from a cow's horn and tanned his buckskin leggings.

Although he doesn't attend a rendezvous every weekend, he has formed a club, the Hell's Hole Mountain Men, whose members like "trekking" - hiking or camping in fur-trade era fashion. A friend and employee, David Miller of West Jordan, got hooked after reading the materials Glover had around the office and joined the club.

Since club members can't always shoot game to eat in these modern times, they carry other kinds of authentic foods when trekking: dried corn (which can be made into many things, including corn meal mush or cakes), dried peas, wild rice, jerky, raisins, nuts, dried cranberries, maple sugar cakes, herbal teas and unsweetened chocolate for hot chocolate.

Glover said the early fur traders referred to themselves as mountaineers and got the name "mountain men" from East Coast newspapers.

The heyday of the mountain man rendezvous period was 1825-40. Before that, those who traded with various Indian tribes for furs had to travel to St. Louis to sell their goods. That changed when one man decided to organize a series of rendezvous in the West to gather furs rather than have everyone make the journey to St. Louis, Glover said.

No one makes judgments about how deeply anyone gets into the rendezvous activities because the whole idea is to have fun. But Glover is eager to inform people about authenticity whenever he can.

Beginners who want to investigate the hobby can attend a "School of the Mountain Man" on June 12-14 at Fort Buenaventura. For information, call Glover at 254-8239.