We added an new ghost effect of children walking in the graveyard. It turned out to be the simplest effect to do but had the biggest impact on all our visitors.
What we did was string a cable from the back of the house to the shop at about 9 feet high. We took 3 10x10 cotton black muslin photography backdrops and sewed them together and strung them along the cable like a curtain. We then filmed our friends kids in white doing stuff along the curtain. Then created a ghost video using the same techniques we always use. Then stuck a projector behind a tombstone at the same place we filmed from and projected it onto the curtain. We created six 5 foot long tube sandbags to hold the curtain down in the wind. We would bring the curtain out at night and setup the projector and just let it run. These photos were taken one night when we paused the projector.