The movie: Return of the Jedi (1984)
In the world of movie titles, there are working titles and title fake-outs. Blue Harvest is the latter. By the time George Lucas was readying the third film in his Star Wars franchise, fan fervor was at an all-time high. In order to avoid leaking any of the film's details ahead of time, George and co. went to great lengths to hide Return of the Jedi's true identity, positioning it was a horror film called Blue Harvest, even going so far as to create a tagline: "Horror beyond imagination."
The fake-out is now fairly legendary; original materials that bear the working title's logo are worth a fortune to collectors.