This isn't a ghost story but it still scared the crap out of me!
When I was about 14 one of my sisters (12 at the time) got sick with some type of flu. The second night her temperature rose quite a bit. I remember going into her room, my parents were there with her trying to cool her down, and she was delirious with the fever. She started talking crazy stuff and her eyes were all glazed looking. She looked and sounded posessed! I was afraid for her, luckily the fever broke in an hour or two right before my parents decided to take her to the ER.
My youngest sister was a sleepwalker...we'd catch her doin' all kinds of crazy things in the middle of the night. Once Mom caught her pulling all the houseplants out of their pots...she thought she was helping to weed the flower beds LOL. It's weird how people are able to speak and even carry on a conversation while they are sleepwalking...always kind of creeped me out though.

I don't suffer from insanity but enjoy every minute of it - Edgar Allan Poe