Reduce or eliminate dependence on foreign oil and make real progress against greenhouse gases.  100+ mpg.  Sounds good.  How?  Electric Cars.  See the teriffic documentary "Who Killed the Electric Car" which examined the mysterious elimination of the all-electric GM EV-1 car. Read about the California Cars Initiative (CalCars), a non-profit organization that seeks to support the introduction of Plug-In Hybrids (PHEVs) through education, lobbying, and technological development. 

What can you do now?  Individuals can't buy plug-in hybrids yet, but they are coming soon.  Conversion companies are producing them now.  GM has the Chevy Volt under development, and Toyota is right behind them.  You can support CalCars with a tax deductible donation.  Sign an electronic petition to encourage car manufacturers to pursue PHEV development.