There are extreme-sports enthusiasts who risk life and limb by racing down impossibly steep surfaces on skateboards. Then there's David Cornthwaite. Clutching his, the 20-something graphic designerfrom Britain claimed a world record the other day. Not for speed, though. For distance. Cornthwaite, you see, had just traveled from west to east across Australia, a trip of 3,618 miles. And within sight of the finish line in Brisbane, he hit a pothole and was thrown to the ground, skinning or bruising knees, elbows, and other body parts. It was his only mishap in five months of enduring searing daytime temperatures (and nights that dropped below freezing), dodging poisonous snakes in the Outback and traffic in the cities, and wearing out 13 pairs of shoes and five sets of wheels. All that exertion also made his pushing leg so muscular that the calf ended up four inches bigger than the other. The trip was 617 miles longer than that of the current record-holder, American Jack Smith. Cornthwaite made it to raise money for charity. He didn't achieve his goal – $100,000 – but says the effort was still worthwhile. And it may not be his last. Where might the next one be? "Don't," he quipped, "rule out ... Antarctica."