Did Nikola Tesla run a car on free energy in 1931? A story featured on EV World describes how Tesla supposedly installed a box containing vacuum tubes in the front seat of a new Pierce-Arrow touring car. Using this power system, he was alleged to having driven the car for a week "at speeds up to 90mph." More here(1).

1. http://www.evworld.com/article.cfm?storyid=1062