All the horsemanship Viggo Mortensen picked up as Aragorn in the ''Lord of the Rings'' trilogy clearly paid off. Here, he's back in the saddle as Frank T. Hopkins, a down-and-out cowboy enticed into entering the ''Ocean of Fire,'' a treacherous 3,000-mile race across the Arabian Desert, by Sheikh Riyadh (played with the usual panache by Sharif) for a $100,000 prize. If only it were that easy. Instead, Hopkins and the equine of the movie's title battle sandstorms, conniving competitors, and even a cheetah before crossing the finish line. Director Joe Johnston doesn't let the CGI effects overwhelm either the action or Mortensen's aw-shucks performance, and no steed has displayed this much star presence since Mr. Ed.
EXTRAS Plenty of horsing around on the ''Sand & Celluloid'' featurette, which includes a how-to on creating edible locusts. But while Viggo's strong and serene disposition may work on the big screen, it renders him apathetic during the interviews.
