Hi Lousia, sounds like a fun party you are going to. I know Salem very well. It's a beautiful city. My brother lives in Beverly, Ma.
In Germany, we celebrate Fasching. That's similar to Madigra, and you see the wildest costumes. Here are two German links…just to get ideas for costumes.

http://www.aufblasbares.de/fasching_frameset.html
http://www.sw-scherzartikel.de/fasching/karneval.html