Is there anything quite so humbling as being a run-of-the-mill athlete in Boulder? After all, the guy leading spinning classes at Flatiron Athletic Club is six-time Hawaii Ironman winner Dave Scott. The co-owner of the Boulder Running Company is Mark Plaatjes, former world-champion marathoner; another local runner, Alan Culpepper, finished fifth this year at Boston. Triathletes migrate here to train. The University of Colorado ski team just bagged its 17th national title. Throw a dart in the air and there's a fair chance it will land on an Olympian—more than 60 live in Boulder County, by one recent tally. Why do so many end up here? Because the 300-plus sunny days and 5,430-foot

My Town: Boulder

Lynn Hill, arguably the best female sport climber ever, on her chosen hometown: "I love to go out my back door and run on the Dakota Ridge Trail. You have to pick a place that has all the things you need. Boulder was the best place I could think of."

altitude make for ideal year-round training. Because the town's decades-long status as Adrenaline Central has spawned a microeconomy catering to jocks: 3-D bike fittings at the Center for Sports Medicine; discount Zen shiatsu sessions at the College of Massage Therapy; mountain-bike clinics with a former pro racer at Outdoor Divas, a shop on the Pearl Street Mall. Because the city owns 43,000 acres of open space with more than 130 miles of trails for hiking, horseback riding, and cycling. Because there's a bona fide job market, anchored by the university and knowledge-economy stalwarts like IBM, Sun Microsystems, Ball Aerospace, and brainiac federal labs. When it comes to measuring a place by sheer athletic excellence per square mile . . . top it or drop it.

REALITY CHECK:
Think life in America's favorite outdoor mecca would be dreamy? Careful what you wish for. Click here to read Marc Peruzzi's take on "The Gore-Tex Vortex."

NEXT BEST:
Burlington, Vermont. Recipe for a multisport boomtown: Combine Green Mountain skiing, Smugglers' Notch climbing, and Long Trail hiking. Blend in sailing and paddling on massive Lake Champlain. Top off with a thriving arts scene and direct flights to NYC. Shake, then chill.