Bill Cosby is back with the “world’s largest checkers tournament” to benefit a foundation named after his slain son Ennis. The Second Annual Bill Cosby Cube Checkers Challenge begins Sept. 25 at a Target store in Chicago. It is the first of four regional events nationwide that will culminate with a championship match Nov. 8 in New York City. The tournament benefits the Hello Friend/Ennis William Cosby Foundation, which helps young people with dyslexia and other language-based learning disabilities. Ennis Cosby, 27, who was shot to death in 1997 while he was fixing a flat tire, suffered from dyslexia.