With the money Microsoft has spent on failed efforts to design hardware, you could finance a trip to Mars.

Its failures make up quite a flop parade: WebTV. Spot Watch. Ultimate TV. Ultra Mobile PC. Tablet PC. Smart Display. Portable Media Center. Zune. Kin phone. If this were ancient Greece, you’d wonder what Microsoft had done to annoy the gods.

There is, of course, an exception the size of Mount Olympus: the Xbox.

With 45 million game consoles sold, Xbox 360 is Microsoft’s monster hardware hit. And today, what will surely be its second monster hit goes on sale: the Kinect.

The Kinect (“kinetic” plus “connect,” get it?) is an add-on for the existing Xbox 360. If you already have an Xbox, you can buy the Kinect for $150, or you can buy it with a four-gigabyte Xbox for $300  if you can find it in stock.