At the train station in Liverpool, England T-Mobile did this great commercial unbeknownst to the daily commuters. They practiced for 8 weeks plus one late night at the station. On January 15th, 2009, with hidden cameras and 400 dancers at 11:00 a.m. their plan was put into action. And some say the Brits are straight laced!!!

Funny, it only took a couple of hours for someone to send me something an American group had done that was just as cool: