Several of the country’s top jockeys will be at the Prairie Meadows horse track in Altoona tonight for Riding Cup-four. Spokeswoman Mary Lou Day says among those on hand will be Jorge Chavez, who rode Kentucky Derby winner Monarchos and Pat Day, both of whom had mounts in Saturday’s Preakness Stakes. It’s a two-team, three race series, with the lowest score winning.While racing usually focuses on the horses, Day says this event is designed to showcase the jockeys. Day says fans will also get to meet those taking part and get autographs.