I tried one with some people one Halloween in a cemetary and everybody was just messing around too much to even pay attention. It was a crappy one from Kay-bee toystores.
I tried a few times with a homemade one (piece of paper with the alphabet) with no extraordinary results.
I found in the closet of an abandoned house. It was a badass, old, creepy board. When I went back to get it and some other stuff the house was locked up.
Anyone ever tried one? Anyone have any good stories?