Ideas for School Spirit Week and School Dance?

I am a student activity adviser at a small school. We are having our 1st ever dance and also a prep rally to pump it up. I'm looking for things to do at the prep rally. We have a school that is coming to play a basketball game with out students but what can we do before the game. The theme for the dance is Masquerade, how can we deco the gym? Please help it is on Nov 1st.