Several hundred bikers rumbled into Sea Cliff this past Sunday afternoon bearing gifts for residents at SCO's Robert J. McMahon Children's Center.  The Who Cares Committee, sanctioned by the American Motorcycle Association, is dedicated to helping children with disabilities on Long Island, and for three decades has been bringing Christmas Cheer to the young people who live at the facility (formerly known as St. Christopher Ottile) located at Downing and Park Avenues that provides 24-hour nursing care, social services and a variety of therapies to children and adolescents with developmental disabilities.