Marilyn Megenity can't stand cars. Most days, she walks to the Mercury Cafe, the restaurant/cafe/community hub she's owned for more than two decades in an assortment of locations, most recently in this comfy two-story building on the edge of downtown. But even this dedicated piéd-ophile has to hit the road now and then. And when Megenity gets motoring, she drives her Peacemobile, a 1982 Mercedes sedan that's fueled by waste, not gas. Megenity uses a fuel hybrid that's processed from reconstituted cooking oil, vegetable products, even fry grease. Painted in bright colors, with banners advertising its eco-friendliness, the Peacemobile is usually parked in front of the restaurant it has come to symbolize. Megenity makes a gas-free life seem easy, practical and worthy of a test drive.