For Christmas when I was about 10-11 years old, my parents bought me an electric blanket. I don't know how they function now, but back then the controls would click on and off to maintain the set temperature. I have always been a light sleeper, and this constant clicking on/off kept me wide awake.
That night, sometime after my parents were asleep, and as I lay tossing and turning, all of a sudden I heard each string on my guitar (which hung on the wall right above my head) plucked distinctly and individually. I'm not sure if I can even begin to express my terror at that moment. Needless to say, I was across the hall and in my parent's room in a flash. My mother didn't believe me and insisted the air pressure passing through the strings could have caused the guitar to make a thrumming sound. But this wasn't a thrumming or strumming sound. This was the unmistakable sound of each string being plucked.
This was not the first experience I had in that room. Some time prior to the above instance, for 3 nights in a row, I was wakened by the portable transistor radio, that sat on my nightstand, playing so softly only I could hear. Now this wouldn't seem so strange except the radio was several years old and the on/off/volume knob had this strange problem that when first turned on, the volume would instantly be LOUD and staticy. I would have to turn the knob further before the static would go away and the volume could be turned down. However, when I was wakened on these 3 nights, the volume was already very, very low. So low it could not be heard across the room.
I never experienced anything in any other room in the house, and several months after that Christmas my then baby brother and I switched bedrooms. As far as I'm aware, that was the end of any happenings in that house.
I want to add that when my parents first bought that house I felt something bad had happened in that bedroom. I have no idea what it may have been, just a feeling. I do know the reason the house was being sold was because of divorce, but have no idea if happenings in that room somehow relates.