Magic box!

Of all the mysteries of humans, the magic box is the most puzzling. It stands mounted on a wall. All shiny and dark, until a humans  points a remote thingy at it. Then it will burst with sound and light, and hypnotize my humans. They can stare at its flasy screen for hours. I have no idea what it is, why it's there, or what's so great about it! 
   It's like the mysterious rectangles all over again.
-Clark the still confused Cat