Famous can be a cult figure or a minor character in a movie or book. Fame need only last few minutes, and that few 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 is 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. If that person was an actor/actress you can go as any of the characters they played.
The whole idea is to get creative. If you enjoy historical clothing, think of the era you like best and find a famous person to be. As for the past, you could dress in Ancient Egyptian garb or 1990s grunge flannel. Maybe the present -- people die all the time in real life, in television, and the movies. Don't forget the future. Stories and movies take place in the future and people die there too. You don't need to look exactly like the dead person (who ever does?). Simply pick some key elements or props essential to the dead person's overall look, and that will convey the idea.
Don't be afraid to be a dead person no-one recognizes immediately. Unless your dead person is someone as obvious as Darth Vader, no-one's going to instantly see the difference between Ceasar and John Belushi as John "Bluto" Blutarsky at the toga party in Animal House. Don't tell anyone who your character is if they don't know. We will be using this unknown information in a game.
