If you've never seen extreme sheepherding, you've got to watch this 3-minute. I just couldn't believe it when I first saw it. And now there's Extreme Sheepdog Trials ($1.99) for the iPhone. You can actually control the game using the same specific whistling sounds that shepherds use to guide their dogs. The object of the game is to guide your sheep using your sheepdog, with multiple levels. See the trailer here.