One day in May, a girl working in Ubisoft's Paris office decorated her window with a post-it note pixel image of Space Invaders. A couple of her colleagues followed suit with other post-it note artwork on the windows.
Well, someone at the BNP Paribas bank headquarters across the street saw the post-it note artwork, and decided to reply in kind with his/her own post-it note gamer art. Thus, escalation.
http://www.youtube.com/watch?v=wXqPw86P8_g
With no signs of stopping, the two buildings have continued this war of post-it note window art since, with a few blogs and forums (and a great deal of French media) keeping tabs on it.
Say what you will, but the French are hardcore. This is proof.