When I think Sean Penn, comedy usually isn’t the first thing to come to mind. Penn is set to play a role in the new Ben Stiller comedy, The Secret Life of Walter Mitty. Stiller will direct and play a “timid magazine photo manager who goes off on an escapade to find a missing negative.” Penn will play the photographer and join an already great cast comprised of Kristen Wiig, Adam Scott, Shirley MacLaine and Patton Oswalt. The script was written by Steve Conrad (The Pursuit of Happyness) [Deadline]