When Hope Thompson decided to pull up stakes in October 2000 and move from sunny Orlando to sometimes snowy Boulder (elevation 5,340 feet), some of her friends thought she was off her rocker.

Turns out, she was off her rocker -- and tying on her walking shoes -- in pursuit of a more active lifestyle. The 76-year-old widow likes to be mobile. She still drives but knows there's a time she won't be able to anymore. And she likes to get out of the house, taking Fit After 50 exercise classes at the Boulder YMCA, going to the theater and walking to the library or grocery store. Thanks to a great bus system, Thompson knows she'll be able to get around for a long time. "I can be independent here as long as I can still move," she says. And as much as she enjoyed Orlando, its public transportation left a lot to be desired. "If you can't drive," she says, laughing, "You're dead!"

In Boulder, as in much of Colorado, life is all about the great outdoors. With hundreds of miles of hiking trails and bike paths, extensive rock-climbing opportunities (for the sturdy of limb), skiing, snowshoeing and many other outdoor activities, there's never a lack of ways to decide what to do with the more than 240 sunny days a year.

A popular local pastime.

Of course, there's plenty to do indoors as well, which is a good thing during the snowy winters. Boulder is known for its strong support of the arts, with a symphony and ballet company of its own. It's home to eclectic shops and restaurants. It also hosts the Boulder Bach Festival and the annual Conference on World Affairs, held at the University of Colorado at Boulder, which brings in international speakers on topics ranging from the arts and domestic politics to the environment and global business. The city has an extensive Senior Services department, which hosts dozens of classes, lectures, workshops and trips to Denver, only 27 miles away.

The city has been so pro-active about servicing its seniors that the over-65 population has boomed and is expected to grow by 65% in the next decade. As a result, the national trend of doctors becoming less Medicare-friendly has created a particular challenge for the city. But there's good news on the horizon: In August, the Boulder Community Hospital is scheduled to open the city's first Medicare-only clinic.

Boulder, Colorado • Population: 95,957 • Nearest big city: Denver (27 mi.) • Sunny days a year: 246 • High July temp: 82 • Low January temp: 4 • More statistics

Admittedly, these benefits do not come cheap. Hope Thompson paid $150,000 for her one-bedroom condominium. Now the median price for condos, which are very popular with retirees, is up to $205,000 -- and median house prices top $400,000.

Nevertheless, the combination of the crisp, clean air, great weather and multitude of activities has an effect that's worth the price to retirees like Hope Thompson. "There are so many people I've been meeting that I think, gee, they're probably younger than I am," she says, "but they're not. They're in their eighties! They don't look it, they don't act it, and they don't seem to feel it!"