Built by Green One Construction Services in Beaverton, Ore., Sage Green is an eco-community that bills itself as “the first Hybrid Zero-Net-Energy development in the nation,” and is perfect for energy-efficiency geeks. The 18 stylish new homes produce more power than they need via solar panels. In other words, buyers of these 1,600-square-foot, single-family units should pay nothing for energy in a year and actually add green energy to the grid. Energy-efficient features include CFL lighting, triple-glazed windows, and high-value insulation. In addition, recycled and locally sourced materials are used whenever possible, as well as low-VOC paints and finishes. Price: just under $260,000 for a three-bedroom home.