are the latest fashion related to the development of the Internet and sites like YouTube. From Wikipedia , the term "flash mob (from flash - short experience and mob - host) indicates a group of people who meet unexpectedly in a public space, usually puts into practice an unusual action for a short time later and then disperse. The meeting is usually arranged through communications via the Internet or mobile phones. In many cases, the rules are explained to the participants of the few minutes before the action takes place. " So the mechanism of information is word of mouth via email, through the classic chain letter, and events ranging from the now classic battle of pillows, the momentary and temporary space in major trade centers, a real ballets such as "musical" in the Hall important railway stations. A particular flash mob was to play the Black Eyed Peas and Oprah Winfrey, the most popular TV anchorwoman in the U.S., a kind of Maria De Filippi. You notice a public initially motionless and cold, which suggests a poor participation in general, quite sad. Then as these were added to the dance in a choreography turned the event into a real flash mob!