It's becoming almost like a ritual of Spring: The unveiling of the "average golfer" finalists for the U.S. Open Challenge.Tiger Woods was the unwitting instigator of the Challenge several years ago when he suggested that a 10-handicapper could not break 100 at Oakmont Country Club the way it had been set up for the 2007 U.S. Open. That's when Golf Digest, the United States Golf Association and