In high school my friends and I were messing around with a Ouija board one night. We had done it before and nothing remarkable had ever happened. We usually did it to try and scare each other or are girlfriends. We all thought it was a joke. That night there was no one else home except the 7 of us and we were all together around the board. One of the girls there wanted to try it. She had never done it before.
This time was different. The board misspelled some of the words the same way every time. It gave answers that seemed really historically accurate for our town (things we neither knew or cared about). Long story short, the "spirit" claimed it was a 10 year old boy who had died on the property in the 1800s and was buried there too in an unmarked grave (my friends house was on a farm in the edge of town). We were all a little freaked out because the board had never been so detailed and consistent. However, we were still skeptical and we were all assuming one of us was trying to scare the rest.
Finally, my friend asked if the spirit could do something to prove he was there with us. It went to Yes and then spelled out k-n-o-c-k. Then the planchette stopped moving. We just all stared at it silently and then there was a rap-rap-rap on the window right next to us. The lights were on outside and there was absolutely no one out there.
We never touched that f-ing board again.