The tale of the enchanting adventures of Baron von Munchausen on his journey to save a town from defeat. Being swallowed by a giant sea-monster, a trip to the moon, a dance with Venus and an escape from the Grim Reaper are only some of the impossible adventures.
This is a "tale within a tale", which while being told, is also happening "at the same time" as well. When the party travels to the "moon", the "King of the Selenites" is played by Robin Williams, whom seems to have a slight problem keeping his head together, or rather "Head AND Body together"
It all started when the Baron and the "Sultan" made a wager that the Sultan was planning on winning. The baron won and (sort of) over-killed the result. This is a comedy, a tragedy, a tale of compassion, noise, and while it couldn't possibly be in any way related to Reality it is true just the same. (We have the film to prove it).