Cross country skiing is the world's most graceful way to tone literally all your muscles -- and get a mountain tan. You can enjoy the sport for an hour at a gentle pace, or look forward to a day-long workout.

Why cross country ski? You can go out with friends, relish an adventure all on your own, take your children for an hour in a special insulated sled, or challenge long downhills on slender skis. There's the chance to glide through snow-laden forest, savoring glorious sunsets while tasting clear air, then come home to your cabin or lodge for wine and a fine meal as dusk falls.

Some people call it nordic skiing, others say ski touring, or skinny skiing. Whatever the name, it's an incredible stress reliever.

And the more you ski, the better you look and feel.

If you watched the Salt Lake City Olympics, you may have thought you have to be young, fit, and unbelievably energetic to nordic ski. Not so! That's like saying if you like to jog, you're obligated to run marathons.

You'll find more women than men out on the trails, and they're just as likely to be in their 50s as their 20s. Most skiers move at a relaxed pace and ski with friends, stopping to enjoy the sunny Sierras in good company.

A few of the people who enjoy cross country are Demi Moore and Harrison Ford, supermodels Emme and Kim Alexis, Robert Redford and Pierce Brosnan. NBC's Dr. Bob Arnot calls it "a sport that can transform you. Nordic skiing has become a fabulous way to see a world few of us can begin to imagine."

It's also one of the safest sports around, especially if you ski at resorts like Royal Gorge, with services like machine-groomed trails, ski patrol, and warming huts. It's low-impact on the ankles and knees too.

And how else can you bask in the sun while burning 800 calories per hour at little more than walking speed? (Just imagine the calories you'll use when you learn to move with a tireless fluid stride!)