In early February 2007, Stephanie Lenz's 13-month-old son started dancing. Pushing a walker across her kitchen floor, Holden Lenz started moving to the distinctive beat of a song by Prince, "Let's Go Crazy." He had heard the song before. The beat had obviously stuck. So when Holden heard the song again, he did what any sensible 13-month-old would do -- he accepted Prince's invitation and went "crazy" to the beat. Holden's mom grabbed her camcorder and, for 29 seconds, captured the priceless image of Holden dancing, with the...