Our PK-5 school usually does a door decorating contest and we have outside judges... it really gets the kids motivated and makes them think about what the week is all about. I've never won the contest, though we try very hard!
Our school did a door contest last year! My class won. We put one of those witch hangings on the door where it looks like she has crashed and on her arm sticking out we placed a can that said beer. Across the top it said, "That's what you get for drinking and driving.