What was supposed to be a thrilling ride down a ski slope inside a giant inflatable ball ended in tragedy for the two Russian men inside. The transparent plastic ball -- called a zorb -- veered off course and sailed over a precipice in the rugged Caucasus Mountains of southern Russia. The man who died, 27-year-old Denis Burakov, was with friends at the Dombai ski resort, where they frequently went snowboarding, on Jan. 3 when he decided to take a ride in a zorb being operated next to a beginners' slope. His friend Vladimir Shcherbakov joined him. An eight-minute video...