Created by “Star Wars” filmmaker George Lucas, these two “droids,” used in "Return of the Jedi" are among the most famous of all science-fiction robots. The little R2-D2 is spunky and resourceful, while his companion, the more human-looking C-3PO, is a bit of a worrywart. Of course, both of these robots were really costumes with an actor inside. Both appeared in the "Treasures of American History" exhibition in 2006 at the National Air and Space Museum flagship building in Washington.