About an hour ago I was on my way back to my hotel after attending an iPhone Film Festival at MacWorld 2012 when I stumbled across a flash-mob dance party at the Powell St. BART Station. The entrance and adjoining tunnel was packed with people dancing to music from portable loud speakers which seemed to be part of a DJ booth with a guy spinning tracks and on the mic. I don't know when it started but watched for about 15min's before it finally ended.