If you want the ultimate in fuel efficient vehicles, you may want to give Dutch inventor and auto designer Allert Jacobs a call. Starting with a 114 mpg Honda Innova motorcycle, Jacobs created a custom fiberglass shell that dramatically improves the bike's aerodynamic profile. He also replaced the Innova's inefficient centrifugal clutch with a manual unit to boost fuel efficiency even further. The net result is a 214 mpg motorcycle that Jacobs calls the AeroCycle. Don't look for one on local roads any time soon, since Jacobs has no current plans for production of the AeroCycle.