Harrison Ford on the set of Indy 4.Courtesy of Lucasfilm.

Movie blog Slashfilm claims they've been leaked copies of the MPAA title registration forms for the fourth Indiana Jones movie. (When producers come up with potential titles for their movies, they file them with the MPAA in order to confirm there's no conflict with other active film projects.) So among the possible titles for Indy 4:

• Indiana Jones and the City of Gods
• Indiana Jones and the Destroyer of Worlds
• Indiana Jones and the Fourth Corner of the Earth
• Indiana Jones and the Kingdom of the Crystal Skull
• Indiana Jones and the Lost City of Gold
• Indiana Jones and the Quest for the Covenant

We guess if these are our options, we'll choose Indiana Jones and the Lost City of Gold, which has a nice thirties serials feel to it. But we're sad that our first choices for the title — Indiana Jones and the Bladder Control Problem and Indiana Jones and the Crowning of New Action Hero Shia LaBeouf — didn't make the cut.

Six Indiana Jones 4 Movie Titles Registered with the MPAA [Slashfilm]