I have a better idea. I'm FULL of great ideas.
All of you buy cheap hundred dollar cars, don't register them, and drive them in a caravan to any city centre and just turn them off, forming gridlock.
Live in the cars. Toss the keys in the sewers. Let's see them clean up THAT mess.
Every city, all at the same time. That would be pretty awesome.
Actually, only block one side of the street, that way the city will be forced to CLOSE the other side for emergency vehicles, fire turcks, ambulances, that kinda thing.