Word is out that Robert Downey Jr., fresh from his success as Tony Stark in the summer blockbuster Iron Man, may be cast in the Brian Grazer/Ron Howard-produced adaptation of Cowboys and Aliens. Based on a graphic novel of the same name, the story shows what happens when Apaches, Apache fighters and settlers join forces to deal with an alien invasion. Downey is up for the part of former Union Army gunslinger Zeke Jackson. Right now, it looks like Cowboys and Aliens will be a front contender in the 2010 summer skirmishes.