Maria Alovert, a Berkely activist, is using old water heaters and the Internet to train the next generation of biodiesel fanatics. Known by the Web handle "Girl Mark," Alovert created the Biodiesel Homebrew Guide zine, now in its tenth edition, and invented the Appleseed biodiesel processor, a piece of equipment found in small-scale biodiesel operations. Alovert's processor is relatively cheap—it bears an equipment cost of just $200—and can turn 30-100 gallons of vegetable oil into biodiesel in just a few hours. In other words, Alovert's processor effectively liberates small vehicle owners from having to purchase biodiesel from large corporate interests. Ride on.