In a ton of movies, Ouija boards are used to contact evil powers from beyond, who give eerie advice and open the gateway for malevolent spirits to reach our cosmos. Generally, this is extremely unusual performance in a game made by Parker Brothers.
Personally, I think it's all misdirection, and the truly Satanic game is Monopoly. Think about it: have you ever played it with your family and not had it result in arguments, tension, and bad feelings? It's like that game was created by demons to spread anger and discord.
What exactly is, then, the scientific explanation for how Ouija and other spiritualist talking boards work? After all, they seem to result in intelligible data.
The answer is the phenomena called the "ideomotor effect." The ideomotor effect, in a nutshell, is that our bodies can move involuntarily without our being actively aware of it, that at times muscular impulses are made without any volition on our part, without any conscious desires or emotions. Breathing, for example, is a well-known example of an ideomotor impulse.
With a Ouija board, however, movement exists that is consistent with our subconscious impulses. Ideomotor effects have been shown to be extremely vulnerable to suggestion; in fact, a person with strong ideomotor activity can also easily enter a hypnotic state.
In fact, our involuntary muscle actions can be made to behave in response to implanted expectations, according to this guy at QuackWatch. In other words, we ourselves are the source of the motion of a Ouija board.
Ideomotor effects seem supernatural, and are the scientific basis behind not only Ouija boards but also "dowsing" and pendulum-swinging divination.
Here's the thing about everything on this blog: you don't have to take my word for it, look it up. But this time I actually encourage you to try this out for yourself. Wear a blindfold, hold a Ouija board, and have a partner read what you produce. It will produce unintelligible gibberish (or alternatively, like the infinite monkeys on infinite typewriters, you'll produce the greatest novel ever written).