To that end, executives at Colonial Williamsburg, which has about 600 costumed interpreters, are going beyond traditional interpretation, creating new attractions with changing story lines, much like theme parks that lure visitors with something new every year. They're adding what one exec calls "scripted spontaneity," featuring "18th-century soap operas" performed by recurring characters for visitors who want to interact with history, not just watch it.

"We're going to introduce characters and scenes in the winter and have the guests follow that family during different adventures throughout the year," says Rex Ellis, vice president for the historic area. "So if you come back, you will see those characters in different situations and different scenarios."

Beginning later this year, for instance, Colonial Williamsburg will focus on different years leading up to the Revolution during different seasons. During the slow winter season, when visitors are often history buffs, it will highlight the small hamlet as it was in 1773. In spring, it will highlight 1774, then jump to the incendiary events of 1776 during the busy summer season, and go back to 1775 and the precursors to the Revolution during the fall.

"If we want to change the way our guests see Williamsburg, they can't assume if they come here in January they'll see the same thing if they come here in summer," says Ellis. "So our programs have to be much more diverse."

Other historical sites have blazed successful paths similar to what Williamsburg is trying.

In recent years, the Biltmore Estate in Asheville, North Carolina, has added a four-star inn, a winery, seasonal special events, horseback riding, events for children, and outdoor activities including river floats, biking, and hiking.