I did mention this to friends and family, and they just said it was strange. No one seems to know what causes it. I thought maybe it was an electrical fault -- like loose wiring -- but someone said no, the radio shouldn't turn on like that even if the wiring had come loose.
The radio incident is even freakier than it sounds since the numbers on the radio dial when it turned itself on were identical to a date in my life when something very bad happened to me. And on the subject of 'haunted' electronics, one of my stereo systems in the house used to turn itself on by itself. That also stopped abruptly and hasn't re-occurred.