(Warning: the article is entitled "Patently absurd", I had never seen that title before!) This is an article by John Naughton about software patents (yes, I know I promised that I would not write about software patents again, but I can't stop myself). Although the article is an adequate introduction to what took place, the item is much more complex than described, but the depiction is good enough to introduce the unwashed to the mysteries of the patent world.
However, what I really liked about the article is that it mentions US Patent 5,443,036. This patent claims to protect:
A method for inducing cats to exercise consists of directing a beam of invisible light produced by a hand-held laser apparatus onto the floor or wall or other opaque surface in the vicinity of the cat, then moving the laser so as to cause the bright pattern of light to move in an irregular way fascinating to cats, and to any other animal with a chase instinct.The mind boggles.