So you're minding your own business at a mall or sitting in a park and suddenly....people are singing and dancing. Yes, suddenly, you're in a Flash Mob! A while ago, it seems like Flash Mobs got so big, and so viral, that it actually wasn't a surprise anymore when one happened.
But then, these started happening less and less...so that's why Al Roker and Hoda Kotb has no idea what was coming when they were doing their usual greeting of people outside their studios in Rockefeller Plaza, check it out!
Photo: Getty Images