When I was in eighth grade I went on a school trip that was called the Louisiana Tour. It was mostly going around to significant sights in south Louisiana. One of the places we went was Myrtles Plantation, which is considered to be one of the most haunted places in the country.
There are all kinds of stories about the place, but at one point we were standing in a room as a part of a larger group and the tour guide was talking about something, I don't remember what. As I'm standing there I start to hear what sounds like someone hitting a piano key. After I heard it a couple of times I started to look around for the source of the noise. I didn't see a piano, but I kept hearing it. So I asked my friends who were standing near me if they heard it, they said no. When I heard it again I said there is it again and that they must have heard it. They thought I was crazy.
So I went back to looking around the room. Everyone's eyes were on the tour guide except for one woman. She caught my eye and pointed at me and then at her ear with a questioning look. I realized she was asking if I heard it too and I nodded.
At this point the tour guide starts telling a story about a soldier who had died there and that he played the piano and multiple guests had reported hearing him playing in the night.
I honestly didn't know what to think, I guess I still don't. I talked to the woman as we were all leaving the room and she had heard the exact same thing as me, but her husband and son had not heard it.