Split the party goers into teams of three and give each team of three people part of a (not ready pasted) wall-paper roll, and 12 safety pins and they have to make an outfit, in say 5 minutes. If you wish, you may specify A dress, Jacket and trousers, etc.
The paper may be pinned on the person's normal clothes, rather than having to make the outfit and then they have to put it on.