Go to a thrift store and buy a couple of mannequins. Pull off the arms and legs and head and separate the torso. Then, pick an area in your backyard and supply a box of props and makeup - fake blood, costume pieces, jewelry, a fake knife. Divide your guests into teams. Now it's a race against the clock to make the scariest tableau (still scene) with the parts you provide. Take a photo picture of each scene, then give out prizes at the end. Fun, but scary!