Invite your friends to come dressed as flesh-hungry zombies because this party is for cannibals only. Hosting a "canni-ball" is all about the food, and all the food is shaped like human body parts.
To set the food mood, buy a plastic skeleton and lay him out on a buffet table -- or parts of him, at least. Be creative with the menu. Brains can be made from molded mashed potatoes, intestines from linked sausages and eyeballs (peeled grapes) can be served by the bowlful. Don't forget gelatin mixes can be molded into pretty much any part you have in mind.
To drink? A bloody punch consisting of cranberry juice, soda and a little extra red food coloring.