I had people dress up as Penguin (tux, top hat, monacle and umbrellla), Catwoman (all black w/ears and tail), Riddler (green scrub bottoms, a green t-shirt w/a purple question mark on it and a green derby from the party store), Two-face (bought a black t-shirt and a white t-shirt, cut them both in half vertically and sewed a black and white half together. pants w/one black and one white leg, 1 black shoe and one white shoe) and Mr. Freeze (I do karate and wore my puffy sparring gear and helmet). I purposely didn't use the Joker because I thought his look and his bio/crimes were too scary. I had pictures of these same character on the walls and a skyline of Gotham City.