Variety reports that MGM and the Farrelly brothers are closing in on their cast for The Three Stooges. Sean Penn is set to play Larry, Jim Carrey is in negotiations to play Curly and the studio is zeroing in on Benicio Del Toro to play Moe. Carrey will gain 40 pounds to portray his role in the film, whose script was written by the Farrelly brothers. The Three Stooges will not be a biopic, but rather a comedy built around the antics of the three characters Moe and Jerome “Curly” Howard and Larry Fine. The Farrelly brothers have attempted to make this film for more than a decade and have…