Here's delightful little video from NPR.
I particularly like the quality of this piece. The audio and video are excellent - one of the hallmarks of NPR, as it moves so much of its programming to the web.
I listen to a number of NPR podcasts regularly and their production quality is the gold standard for everyone else.
Try as you might, you can't walk in a straight line without a visible guide point, like the Sun or a star. You might think you're walking straight, but as NPR's Robert Krulwich reports, a map of your route would reveal you are doomed to walk in circles.