You peek into the aerobics room on your way out the door and see that they're kicking up a storm in there. At first, they look like either an array of Rockettes or a Broadway dance audition. Knees are pumping, legs are snapping, and feet are flying everywhere.

And let's not forget the sweat. It's pouring down by the bucket.

Sure, to the curious on-watcher, it would be difficult not to be swept up into the most publicized cardio craze to capture the nation in nearly two decades.