Couched between Boston and D.C., Estes Park sits at No. 14 on TripAdvisor's freshly released Travelers' Choice Top 25 Destinations in the United States. Few Coloradans would disagree. If you've lived here long enough, you've probably stopped in Estes for a visit before taking out-of-state guests on a warm-weather sojourn into Rocky Mountain National Park. All those extra visitors contribute to the tiny town's tax purse, which swells to about $1.3 million a month in summer. In winter, however, that number drops to a chilly $250,000.

The Elkhorn Project wants to balance to the seasonal lopsidedness with a year-round adventure park (Coloradoan). Plans include a performing arts center and museum, biking, hiking, horseback riding, tubing, skiing, and zip lines—but they're not in the works yet. Organizers are hoping to pay the $50 million price tag with a Regional Tourism Act grant from the state, although just two are issued each year.

The investment could pay off handsomely down the road, as the Colorado Springs Convention and Visitors Bureau knows. There, tourism's economic footprint is $36 per second (McClatchy-Tribune). Denver is expected to make a good showing in this regard as well: Orbitz says the Mile High City will be the nations' fifth-most-visited urban spot this summer, despite high flight and hotel prices (Denver Business Journal).