I always thought that the Joker looked the best/scariest when he was seen through glass and the only details you can really make out are his dark eyes and red scar smile. One of the movie posters showed him writing "Why so serious?" where you get this effect. In the film itself there's a quick moment as he's leaving the meeting with all the mobsters (you know, the magic pencil trick scene) where he kicks the door open behind him to leave and as it swings shut you get a glimpse of the Joker behind frosted glass and the smile and the eyes are the only thing that you can really make out. Very cool look. Thought I'd try for that here.
