Roger Yepsen grew up in a house of the future, a John Johannsen-designed Modernist slab near Schenectady, N.Y. Sunday drivers would brake to a stop just to stare at the home--and through it. Half of the steel-frame structure's walls were glass, giving gawkers an experience that anticipated reality television. Today, Roger lives with his wife and children in a 200-year-old stone Pennsylvania Dutch farmhouse that has been expanded with a timber-frame addition.