Last year I was Spongebob Squarepants. Got two pieces of cardboard and glued a bunch of yellow sponges to them, and wore yellow shirt/pants with yellow kitchen gloves. It turned out pretty well, but was a bit hard to move in, though i'm just glad it didn't rain!
I was wanting to do the Jack in the Box guy, but trying to make it would be a bit much this year. So, i've settled on being a snowman. Got a bunch of that "snow" material used for Christmas displays, and i'm going to attatch that to a bunch of clothing and a ski mask I got for my head. I've also got a top hat and will put buttons on the mask for the mouth. A bit cheesy, but it should be ok.
At least i'll be able to move around this year. Still hope it doesn't rain though.