Dean Karnazes has run 350 continuous miles through three sleepless nights, ordered pizza during long runs, and inspired fans the world over with his adventures. So what does a guy like this do when he wants to face the ultimate test of endurance? He runs 50 marathons in 50 states-- in 50 consecutive days.With little more than a road map and a caravan packed with fellow runners and a dedicated crew, Dean set off on a tour that took him through a volcanic canyon in Maui in high humidity and 88-deg...