The Mystery is Solved.
There's this lilting piano music that I hear from time to time outside my apartment. I've heard it early early in the morning, and now at almost midnight. I think it's 24 hour thing. It sounds like it's coming across the field, from the cemetery across the street. My boss mentioned it one day in passing, confirming that I'm not nuts! So I heard it tonight, traipsed across the field, across the street, across half of the cemetery, and saw a chapel with the lights on. Apparently this music is piped continuously out of the chapel, and the chapel lights are left on, for those people that visit in the dead of night?! Who knows. Very weird!