My brother and a co-worker lead retreats one summer at St. Vincent's school for boys in San Rafael, CA. People think the place is haunted and my brother and his co-worker had some unexplainable experiences. They lived on the premises and when not leading a retreat, would often be the only people on the premises.
A couple stories I remember when they were the only ones there;
1) He and his co-worker were in one room when they heard a guitar in another room strummed.
2) They were listening to music when it cuts out. They go to the room with the stereo to see what happened and all the mechanical lever switches were turned off.