Winter Trails Day (annually, in January)               

Winter Trails Day is a nationwide event, with free or discounted access to many cross country (nordic) ski trails and snowshoe trails, free tours, free rentals, and that sort of thing.

Unfortunately Colorado nordic areas have very poor participation in Winter Trails Day, but there are a couple of snowshoe only events scheduled:

For 2012, Winter Trails Day is Saturday January 7, 2012. With an extra snowshoe-only event on Saturday January 14, 2012 at Estes Park. The bonus for the Estes Park day is that admission to Rocky Mountain National Park is free that day!

Winter Trails Day Events in Colorado:

Echo Lake (exhibit anchor site) 10am - 3pm.

Estes Park Winter Trails Event:
The Estes Park Winter Trails event takes place the following weekend, Saturday January 14, 2012, and offers free snowshoe rentals from retail booths set up in downtown Estes Park, for use in Rocky Mountain National Park. Rocky Mountain National Park is also free this weekend, making a great excuse to come out and try some snowshoes. My favorite area to snowshoe in RMNP is the Bear Lake area, with several interesting trails, or just walk around the lake.

Check the Winter Trails site for the schedule and offerings: