Weird lighting issues

den built-ins
Originally uploaded by modernemama

This is starting to freak me out - big time. This evening I went to have a sundowner at the beach and watch the sun set. I left at about 6:30 and although it was too hazy for a proper sunset there was a true harvest moon to make up for it.

When I got home, though, I was greeted by this in the den, The lights over the built-ins had come on. Not the bar lights that scared me on Monday , but the ones on a different switch.
I didn't put them on, in fact I haven't touched any of the switches in the den except the table lamps since Monday night because I was afraid I'd have to go to the basement again and turn the entire house off and on, which means I have to rest the airport and the TV cable has to reset itself. A hassle.

So, WHAT IS GOING ON? Help, somebody, and quickly, please.


UPDATE 9:12 PM
The chandelier over the coffee table in the den (you can see it in the photo between the built-ins) came on and five minutes later went off again. Is this some new random motion sensor thing? Again, HELP...........