You've probably seen the video from Antwerpen Centraal, which was a promotion for the Flemish TV show "Op zoek naar Maria".
Yesterday, at Brussel Centraal, this mob erupted. This time, they're promoting a series of charity bicycle races- see the embedded video at the bottom of the page:
http://www.standaard.be/artikel/detail.aspx?artikelid=DMF20100511_186