You can still achieve some sustainable progress by buying a car that runs on gas, but that manages relatively high mileage. And you can max out your mileage by going for a stick shift.
At this year's Los Angeles Auto Show, the 205-mile per hour, $100,000, 2009 Corvette ZR1 is relegated to the very rear of the Chevrolet exhibit, like the "adults only" section in video stores.