In this video, Derren Brown controls a shopping center full of people to make them all at the same time do somthing which they are unaware of. its in realmedia format :(
Derren Brown - Mind Control (http://www.channel4.com/entertainment/tv/microsites/M/mindcontrol/streaming/suggestion.ram)

That is rather creepy. That would be interesting to have been there, seen how your mind reacted.

yeh :) theres more at http://www.channel4.com/entertainment/tv/microsites/M/mindcontrol/video/index.html