Box Office: Vin Diesel propels 'Riddick' to No. 1 debut

"Riddick" starring Vin Diesel debuted to $18.7 million over the weekend, good enough for the No. 1 spot. "Lee Daniels' The Butler," meanwhile, held strong at No. 2 with $8.9 million, while Spanish dramedy "Instructions Not Included" did well in its expansion, grossing $8.1 million in third place.