Smug about your 65 mpg Prius potential? Don't be. A little car from up-start Riversimple looks set to deliver the equivalent of 300 mpg, running on hydrogen and utilizing a network of small fuel cells to power four motors, one per wheel. The recently unveiled prototype manages 240 miles on just 2.2 lbs of hydrogen, has a top speed of 50 mph, seats two (reasonably) comfortably, and looks a little like a smiling, new-age Citroen 2CV -- but will hopefully be a more enjoyable to drive. That considerable range means that the relative lack of hydrogen distribution stations is less of a problem (until you can get one for your garage), and an estimated monthly lease price of just £200 (about $330) makes it potentially affordable. The only question now is availability of the cars themselves, and since nobody's talking about that you needn't worry about delaying that appointment with your local Toyota dealer.