The 20 th annual Desert Challenge Games for disabled athletes will be held May 19-23 in Mesa.  The competition is open to all U.S. and international athletes with a physical disability, ages 6 through adult.  Athletes will compete in track and field, weight lifting, archery and swimming.  This year Mesa is one of two locations in the U.S. to host International Classification.  Thirty-two athletes are expected to compete and obtain their International Classification on Wednesday, May 19 and Thursday, May 20.  Athletes from Mexico, Canada, and Bermuda are already