Heath Ledger plays an evil, sociopathic version of The Joker in the latest Batman movie, but in other forms the character has been more of, well, a joker. And sometimes he's been downright goofy.

This story looks at how The Joker came to be an important Batman villian and how he has been played through the years by actors ranging from Cesar Romero (in the 1960s TV show) to Jack Nicholson and Heath Ledger. It also explains where his bizarre facial appearance came from.