cross country skiing
Spectacular Volcanic Lake at Crater Lake National Park with multiple rim hikes, Rim Drive, can hike to lake level at Cleetwood Cove, see millions of stars on clear nights. http://www.nps.gov/crla/index.htm: "Like No Place Else On Earth Crater Lake has inspired people for thousands of years. No place else on earth combines a deep, pure lake, so blue in color; sheer surrounding cliffs, almost two thousand feet high; two picturesque islands; and a violent volcanic past. It is a place of immeasurable beauty, and an outstanding outdoor laboratory and classroom."