This is just a small thing really, but I thought it was pretty cool when I first saw it (and testament once again to Apple's eye for detail)! In Dashboard, open a world clock widget (if you don't already have one running); After it finishes loading and displays the time in your location, flip it over and change the location to somewhere new (preferably a continent or city as far away from your own as possible). Click 'Done', and then watch the nice little animation! 