Don't know what exactly controls Ouija boards, whether its demons, or your subconscious, or what... but I've used 'em a few times by myself, and they "worked". I can honestly say that I didn't consciously move the planchette, and it spelled out things.
One of the few times I used it with another person, it got really specific, and once it even started moving around in figure eights by itself. I found out later that supposedly this means an "evil spirit" has taken control. I don't know about that, I just know what happened. On my forum, I was looking for Ouija board stories too, but it seems like nobody has any. Ah well.