Greenlings: How can I pimp green my ride?

Driving a car that's had more than a few birthdays and wish you could make it greener? Whether your concern is centered on air quality, climate change or just saving a few bucks as fuel prices rise, there are many ways you can accomplish this goal using your common sense or perhaps a little modern technology. We've compiled some of these for your perusal below the fold but since we have some pretty astute readers, we hope you'll leave your own su...