Some of the scans not included in this show the Joker blowing up tanks and the like, generally terrorising the police and stuff like that. Basically business as usual, only on a grander scale, I think.
Basically, to paraphrase Batman, the Mask has such an influence on it's wearer that it probably takes away from the creativity of someone like the Joker. He can do anything, but he'd most likely resort to the most obvious thing (like using a giant bomb to blow up Gotham), than anything truly imaginative.