Okay, so it's not in the spirit of Valentine's Day to talk about divorce. But that's not stopping Katie Alvord from advocating mass divorce -- from car culture, that is. As the author of "Divorce Your Car! Ending the Love Affair with the Automobile," Alvord puts her money where her mouth is. She's so hard-core that she bicycles in Michigan's Upper Peninsula in blizzard conditions, takes Greyhound and Amtrak to book-tour destinations, and will only hitch a ride in her spouse's hybrid Toyota Prius when absolutely necessary. Get motivated to live by your principals -- read about the awe-inspiring Alvord, only on the Grist Magazine website.