Before Jay-Z declared war on Auto-Tune, it was regional rap dances — most prominently performed by Soulja Boy, the Atlanta teenager whose Superman dance helped make "Crank That (Soulja Boy)" a super-smash in 2007 — that were enemy No. 1 of "real hip-hop." But despite the laments of any number of curmudgeonly New York rap heroes, this year has brought us another batch of playful coordinated moves motoring Southern hip-hop hits, mostly courtesy of eager underage kids from small towns. They're all about what to do with "it," namely: lean, rock, stop. These aren't the newest dances, but right now they're the most popular, and are likely to last through the warmer months. So, what moves will you not be learning this summer?