This party has only one rule:
Of course, the definitions of "famous" and even "dead" are subject to your interpretation.
Famous can be a cult figure or a minor character in a movie or book. Fame need only last 15 minutes, and that 15 minutes can be buried in a Shakespearean subplot or forgotten in last year's tabloid news. Real people who actually lived can be famous. Fictional characters from any media can be famous.
Dead can be everlasting, but resurrections are okay too (and more common with fictional characters). Momentary death is still death. Missing or presumed dead counts too.
Don't forget the undead -- vampires, mummies, and ghosts are all dead enough. And you can appear as the person looked at any point in life or at any point in death.
The whole point is to get creative. You can pay homage to a favourite author or poke fun at a trashy insta-celeb. Express your sense of humor or indulge your dreams through a famous dead costume.
If you enjoy historical clothing, go to the era you like best and find a public figure to be. History is nothing more than yesterday, and you could dress in Ancient Egyptian garb or 1990s grunge flannel.
Or stick with today -- contemporaries die all the time, both in real life and in television and the movies. You can wear what you do everyday, yet with the addition of a single prop, you'll look the part of that character.
We hope you have fun creating your famous dead person, and we'll see you around Halloween!