See Today's Green Minute's Episode #2, "The Missouri Hockey Puck"

This is the story of how the University of Missouri developed a hockey puck-like object, made from corn (of which Missouri has an abundance) that can hold an enormous amount of methane. A methane-propelled car would be an obvious application, and if the methane it stores comes from a landfill, the hockey puck brings about an environmental triple play: 1. cars burn cleaner, 2. old corncobs are used productively, and 3. methane can be burned instead of petroleum.