A friend and I used to play with a board all the time when we were teens. The last time I ever played with it was at her apartment, we were alone, it was the middle of the day, and we sat in the middle of the living room floor calling spirits. Usually it wasn't too scary or anything, but this one time we got a 'bad one'.
The board started going nuts, spelling really fast, then a porcelain figurine smashed to the floor in her bedroom and the kitchen cupboards started banging open and shut. We ran out of there SO FAST and refused to go back until her mom came home from work. She moved a few months later. Hope we didn't leave a nasty spirit in there for the next tenants!