At the MTV VMAs, Shia LeBeouf announced that the title for the new Indiana Jones movie will be Indiana Jones and the Kingdom of the Crystal Skull, which narrowly beat out Shia LeBeouf and the Facial Hair of a 6th-Grade Mexican.
According to a helpful wikipedia entry:
A modern legend claims that there are 13 crystal skulls worldwide, of which five have actually been found, which have mystical powers and are of ancient origin. Such claims remain unproven. New skulls carved from crystal are made and sold regularly.
They also are a great place for hippies to store their shitty coffee table candy as they match the stupid African masks on the walls.