Why Are Cats So Obsessed With Laser Pointers?

(via How Stuff Works) Not much in this world is quite as amusing as watching a cat freak out over the little red dot of light produced by a laser pointer. While you sit chuckling on the couch, twitching that $6 device around in your hand, your cat is experiencing real moments of heroic desperation. It’s great exercise for indoor cats, but why do cats find this activity compelling?