Although ouija boards are viewed by some to be a simple toy, there are people who believe they can be harmful, including Edgar Cayce, who called them "dangerous."[6] Critics warn that "evil demons" pretend to be cooperative ghosts in order to trick players into becoming spiritually possessed.
Some practitioners claim to have had bad experiences related to the use of talking boards by being haunted by "demons," seeing apparitions of spirits, and hearing voices after using them. A few paranormal researchers, such as John Zaffis, claim that the majority of the worst cases of so-called demon harassment and possession are caused by the use of Ouija boards. The American demonologists Ed and Lorraine Warren, stated that "Ouija boards are just as dangerous as drugs."[7] They further state that "séances and Ouija boards and other occult paraphernalia are dangerous because 'evil spirits' often disguise themselves as your loved ones—and take over your life."[7]
http://en.wikipedia.org/wiki/Quija_Board
I know some people believe in ghosts/spirits and I've always wondered.