One of the most novel and intriguing elements of social media is the ability to contact and connect with a disparate group of people who all have a common interest and a loosely tied social network. In Israel Nefesh B'Nefesh organized and conducted an amazing dance flash mob, attracting participants via Facebook.
The mob performs an almost 3:00 minute choreographed routine to celebrate the upcoming Hanukah holiday in the hear of the Jerusalem shopping and entertainment district known as Ben Yehudah Street. The performance is reminiscent of a 'Mob' executed by Improv Everywhere - a ad hock troupe from New York which was recently featured on NYP's This American Life.
I love the creativity and organization involved. In particular the leveraging of a social network system to bring together such a large group so quickly is what is most inspiring and impressive. I think the below video is even more entertaining since it gives so much great back story into the making of a flash mob.