Perfect for celebrating Earth Day, Citizen Sugar is offering one lucky winner $500 in gas relief. ("Gas relief." Har.) All you have to do is register and take a brief quiz (e.g., "how much does it cost to fill up a 2008 Hummer 2 [H2]?"), and then you'll be be entered in lottery. And if you win, you'll can temporarily stop whining about the price of gas these days. Oh, and the contest is......