We're hard at work planning our upcoming live show, so we bring you this favorite from the last year: Zumba. Zumba began as a mistake: aerobics teacher Beto Perez brought the wrong music to class, then improvised a dance routine to go with it. For his students, it was more fun than work — and it eventually grew into one of the biggest fitness brands in the world. PLUS for our postscript "How You Built That," how Alex McKenzie is hoping to upgrade the menu of your neighborhood ice cream truck by offering exotic flavors, high fat content, plus low-guilt options for the health-conscious.