Have your children form a circle with one child in the center. The child in the center will  have a shield to protect himself from the "fiery darts of the evil one." The children in the circle, using Nerf balls, will attempt to hit the other family members in the center. If the child in the center is hit, he or she will change places with the one who hit him or her. Start out with only one  Nerf balls and then gradually increase the number of "fiery darts."