Poltergeist

That might look like just an ordinary kitchen TV, but it's possessed by a poltergeist. It sometimes turns on in the middle of the night, all by itself. The kitchen is just a few steps from the bedroom so I'll wake up to flashing lights and noise-- just another weird dream? Or sometimes it's blaring away when we walk in the door, and no one ever watches television here during the day, except the poltergeist.

So we've learned to turn the sound down when we shut it off, so not be awakened by an infomercial at 2 am.  I could go on Ask.com and probably get a mechanical or electronic explanation from some smarty-pants, but it's more fun to blame it on our poltergeist.

A poltergeist is the apparent manifestation of an invisible but noisy, disruptive or destructive entity. Most accounts of poltergeist manifestations involve noises and destruction that have no apparent cause. Reports also include inanimate objects being picked up and thrown as if by an invisible person; noises such as knocking, rapping, or even human voices.