Mark Scolforo.

The central Pennsylvania town of Mount Gretna is a throwback to the period more than a century ago when the summertime get-togethers known as Chautauquas were practically a craze. They brought education, entertainment and a dose of religion to communities in the Northeast, across the Great Lakes, into Canada and beyond. These days the little mountain community that’s a two-hour drive west from Philadelphia springs to life every June, July and August. Its year-round population of about 1,000 more than doubles and its picturesque front porches become filled with energetic cottagers who punctuate their days with cooking lessons, nature walks, yoga, professorial lectures, music and plays.