Besides Galliano, my two other favourite crazy make-up looks are from Dior (left) and the Lacroix haute couture (right) show. Both redefines the upper and lower part of the eyes making their eyes look HUGE. They are in essence however, the opposite of each other. While Dior uses a sharp white base, Lacroix uses a smokey black base. Either way, I'm loving both of them. Go for the Dior look if you want to look feline and the Lacroix look for something a bit darker. 
A bit more subtly, we have the smokey eyes of the Chanel haute couture (left) and the Balenciaga (right) show. Just go heavy with the eye liner and the smudging. If you do have a costume, these would be more subtle looks for you. You don't want to take away too much from the outfit now do you?And as for some simple DIY ideas: You can be forks/knives/spoon with alumninium, a piece of steak and ketchup/mustard to go with that. You can be Tetris pieces. Pacman and the ghost. Or a Twister board- just wear white and stick colored dots on yourself and carry the spinning thing!
Happy Halloween everyone!
Image Source: Style.com