The New York Times caught up with Heath Ledger in London, whilst being an interesting insight into the actor’s real life habits, there are also a few interesting Joker muses in the piece.
Here too was his Joker diary, which he began compiling four months before filming began. It is filled with images and thoughts helpful to the Joker back story, like a list of things the Joker would find funny. (AIDS is one of them.) Mr. Ledger seemed almost embarrassed that the book had been spotted, as if he had been caught trying to get extra credit in school.
Via BatMovieNews