Drivers Paint Rosenthalerplatz
In Berlin, a "group of cyclists" dumped many gallons of paint into the middle of Rosenthalerplatz, letting pedestrians, cars, and bikes create a colorful collective work of art. Amateur video below.
It's fun. A little messy, perhaps, but fun. According to Abitare, "The creators of the project posted signs on post nearby explaining that the paint wasn’t harmful and would simply wash off with water." There's a great set of photos on Flickr.