Hold the Fries; Just Some Grease Please

Mexican pig lard, Alaskan fish oil, and lots o' fast food grease powered what two professional kayakers are calling the longest road trip ever made without gasoline. The 21,000-mile trek from Alaska to the tip of South America—in a converted Japanese firetruck—took nine months, with the duo stopping frequently to give talks on the virtues of biofuel.

Twenty-somethings Seth Warren and Tyler Bradt aren't done: they're rejiggering the truck to drive across the U.S., this time on algae. Warren says he wants to show people they can run cars on all kinds of oils. "We don't think vegetable oil is the answer to all the world's problems, but it's definitely one of them." (More climate change stories.)