An X-Prize for autos is in the offing. Automotive efficiency is a significant factor for our energy budget. The Rocky Mountain Institute has identified three areas ripe for improvement, improved engine efficiency (including hybrids), reduced aerodynamic drag, and reduced weight. In the three decades since the oil shock of the 1970s, the automotive industry has made good progress in the first two areas, but weight has increased with the addition of safety features and luxuries with little effort to contain weight. An X-Prize for autos could spur use of carbon fiber and other light weight, high strength materials.