Wearing a Halloween costume at work?

I work weekends at a family-friendly breakfast restaurant. There's banter going on that the waitresses have the option of wearing Halloween costumes on that day. Normally, we wear polo shirts and have a no-denim policy. I think it would be fun to wear a costume, but it can't be too big or too fussy or too y as I still have to clean tables, deliver food, and interact with children. Any suggestions? Pictures/links helpful.