Every movement has its lunatic fringe. As Middle America has enthusiastically hiked, biked and paddled into the middle of nowhere, a handful of hard cores have headed straight to the outer limits. Some are athletes whose skills have outgrown conventional challenges. Some were just born to be wild. All of them are hellbent for thrills. You might navigate your mountain bike down a steep and winding trail. They slip into high gear and race down faster than a lot of people drive. You might schuss a black-diamond run. They ski off cliffs. You might climb an impressive peak. They run 150 miles from Death Valley to the top of Mount Whitney–in July. They call their passion extreme sports. You might call it crazy.

Unhinged: The world has always had daredevils, of course, but rarely have they been so organized. Or so obvious. The exploits of the unhinged are no longer just the stuff of ski-town legends. Bad dudes now sell everything from beer to burritos, carving, leaping and racing across your Trinitron, leaving rebellious brand images in their wakes. They also entertain weekly on “MTV Sports.” Over the past few years, contests have sprung up to provide a public–and sometimes lucrative–forum for athletes to exercise their outdoor one-upmanship. Mountain bikers are perhaps the best organized of the pros, with both national and worldwide circuits. But sports like white-water rodeo, extreme skiing and Snowboarding, and back-country endurance racing are also picking up speed.

The race to the brink, like most things American, is driven by cash. Equipment makers want the 5.7 million mountain-bikers-at-large to see the roughly 900 pros bolting over boulders with their brand of gear. Colorado’s Crested Butte ski resort wants weekenders to marvel at the snowy heroics of the U.S. Extreme Skiing Championships–and stick around to take some runs of their own. And bigger corporate fish have televised events to sponsor. The first ESPN Extreme Games, coming up later this month, will feature extreme mainstays like mountain biking, as well as more esoteric pursuits like street luge and sky surfing. (Street lugers hurtle down hills feet first, lying on a wheeled sled; sky surfers jump out of planes and ride the air on boards as they free-fall. Yes, they have parachutes.) ESPN easily sold six “gold level” sponsorships to companies like Nike, Chevrolet and AT&T. A winter version may be next.

Then again, when you’re flying 40 feet through the air on skis into an absurdly steep, rock-strewn couloir, it hardly matters whose logo you’ve got plastered on your back–unless it’s big enough to use as a parachute. Extremists take the money because it’s there. They take the risks for reasons of their own, and death does happen. Two years ago an extreme skier was killed at the world championships in Alaska after a cornice gave way as he scouted his route. Last winter legendary big-wave surfer Mark Foo died at an infamous northern California break called Maverick’s. And in April a new multi-sport endurance event called the Eco-Challenge sent at least six competitors to the hospital, several with life-threatening problems ranging from dehydration to exertional rhabdomyolysis – an unpleasant condition in which the body begins digesting its own muscle tissue. Still, as organizer Mark Burnett cheerfully points out, “nobody died.”

The Eco-Challenge, based on an international adventure race known as the Raid Gauloises, is billed, with some hype perhaps, but not much, as “the toughest race in the world.” In the inaugural running, 50 five-person teams set out to race 24 hours a day for seven days over 370 miles of remote terrain in southern Utah. Fewer than half finished. The course began with a marathon-length horseback segment, in which team members took turns riding and running alongside for 26 miles. The teams then slogged through narrow, water-filled canyons, sometimes swimming with backpacks through 50-degree water; hiked more than 100 miles across stretches of waterless desert; negotiated 1,200-foot cliff faces on ropes; rafted class IV (advanced) rapids on the Colorado River; and capped it off with a 12-hour, 50-mile canoe paddle across Lake Powell. A New England race is planned for next week’s Extreme Games.

The first Eco-Challenge attracted entrants ranging from Navy SEALs to a 72-year-old great-grandmother. There were people like Marshall Ulrich, 43, a longtime ultramarathoner who has won the annual 150-mile Badwater footrace from the parched depths of Death Valley to the frigid summit of Mount Whitney, 14,495 feet above. He finished the new race. Others, like Valerie Ringo, didn’t. The 28-year-old personal trainer from Los Angeles got lost and ran out of water on the race’s fourth day. Though she downed some drinks other racers shared with her–and all of her con-tact-lens solution–Ringo became severely dehydrated. She stumbled down the trail, slurring her words, distracted by hallucinatory visions of fish and furniture her mind cast on the canyon walls. She was choppered out at 3:30 a.m. but says she’ll definitely be back next year: “Think of how much I’ve learned.”

And so it goes in extreme sports. Live and learn; learn or die. “There’s no future in not being seared,” says Dean Cummings, 29, who won this year’s World Extreme Skiing Championships (WESC) in April outside Valdez, Alaska. “You’ve got to have some fear of what you’re doing or else you don’t belong out there.” WESC is the premier event in a sport that now boasts an almost endless winter, with extremists migrating in summer to keep the thrills coming. But not just anyone can compete. Entrants are carefully vetted: application forms ask about mountaineering experience and avalanche training and require skiers to list their top four extreme descents. The contest’s coed field of 35 is deposited by helicopter atop wild peaks. Organizers warn of steep rock-rimmed couloirs, sheer wind-swept faces, precipitous overhanging cornices and avalanche-prone slopes.

Judges award points for aggressiveness, form and difficulty. Skiers must wear avalanche beacons, which help rescuers locate and save them. Scary–but fun, too, says Cummings, who was once caught in an avalanche in Colorado, escaping seconds before he’d have followed runaway tons of roiling snow over a 100-foot cliff. “It’s basically the most incredible buzz you could ever have. Time stands still. You couldn’t care less about what’s going on in the world–let the governments do their thing. Nothing matters except for what you’re doing.”

Extreme sports tend to attract extremepersonalities. Take Missy Giove, 23, women’s downhill-mountain-bike-racing world champ. She and her cohorts pedal around hairpin turns, through mud and gravel, at speeds that can exceed 50 miles an hour. “I wanted to join the NFL when I was little,” Glove says. “I thought I was going to be Lynn Swann, the wide receiver for the Pittsburgh Steelers.” That didn’t work out, but at 14 she delivered Chinese food on a bike in Manhattan–also a full-contact sport. Five years ago, a friend dared her to enter a mountain-bike race in Vermont; she won. “I kept crashing the whole time,” Glove recalls. “I was taking dirt sample after dirt sample. I had no idea what the hell I was doing, but I loved it. The speed was so out of control!”

Rag-dolling: Thrills are addictive, but an adrenaline jones can be beaten. Jay Liska admits he’s thinking about it. In this April’s King of the Hill extreme Snowboarding championship, outside Valdez, the 29-year-old pro sailed over a 20-foot cliff and landed on some rocks. “I stared crashing–we call it rag-dolling,” he says. “I was going down the mountain, pretty much cartwheeling all the way.” He dug his legs into the ground to stop himself. “My muscles ripped my left kneecap straight in half. I was going to get up and keep going but my whole thigh muscle was connected to nothing.” He caught a medevac flight out. The next day, a rider practicing nearby was killed after plunging into a crevasse. “He was buried inside the glacier,” says Liska. “They got him out after four or five hours.” Liska says he’s now planning to tone down his riding and devote more time to running his Snowboard shop in Anchorage. His wife is pleased.

Who:

Surfers Laird Hamilton (above) and Buzzy Kerbox.

A surfing variation. They use Jet Skis to tow themselves into position, then catch waves as big as 25 feet, sometimes several miles off the Hawaiian coast.

“It’s dangerous, but it’s like an addiction,” says Kerbox. “The bigger wave you ride, the bigger wave you want to ride.”

RUNNING WILD

Colorado ultramarathoner Marshall Ulrich, 43.

Ulrich has won the 150-mile Badwater race, set a record for running 310 miles across Colorado in 88 hours and has run up Pike’s Peak four times in a day.

“I want to do something that somebody else hasn’t done. Every year.”

TOUGH AS NAILS

California’s Helen Klein, 72.

Klein finished this year’s multisport Eco-Challenge race and has logged some 43 marathons and 92 ultramarathons since taking up running at 58. She and her husband organize 100-mile races.

“I’d rather wear out than rust out,” says Klein, shown climbing during the Eco-Challenge.