http://www.publicadcampaign.com/nysat/
This is the coolest project I’ve read about in weeks. Basically, people painted over existing commercial billboards, often replacing them with art.
From their about page, emphasis mine:
First and foremost the NYSAT projects targeted a single company called NPA City Outdoor, otherwise known as Contest Promotions. Here at PublicAdCampaign we oppose all outdoor advertising in public spaces, legal and illegal, as it alters the physical and psychological landscape of our shared environment for the worse, treating us as self interested consumers. The choice to target NPA was made for two reasons and was not the result of personal issues with the company. The first is that NPA happens to operate completely illegally in NYC making it a prime target to challenge outdoor advertising’s use of our public environment. This also made it more likely that people would be willing to whitewash approximately 20,000 square feet, or 120 illegal street level billboards, given that they were illegal in the first place. The second reason is simply that all NPA street level billboards can be reached from the sidewalk and are therefor accessible enough to even consider for a project of this scale.
NPA City Outdoor operates over 500 illegal street level billboards in the 5 boroughs of NYC. Despite this the city has been either unable or unwilling to deal with this problem directly. As engaged citizens the participants in this project have taken it upon themselves to remedy this problem. In doing so they have realized their potential as public citizens by taking it upon themselves to create an environment that is a direct result of their actions.
In an effort to illuminate the illegal advertising issue in New York, over 100 participants from as far as Toronto and France, took it upon themselves to reclaim these spaces for public communications and realize their potential as public citizens concerned for our shared public environment. In an action coordinated by PublicAdCampaign, participants eliminated the illegal content by whitewashing over all the NPA ad locations below 23rd street, then returning to the newly liberated locations to create public works of art and commentary.
The first non violent civil disobedience project happened on April 25th 2009, and resulted in the whitewashing of over 120 illegal ads and the creation of countless public works. There were 4 arrests in the first action. The second project on October 25th whitewashed 116 illegal billboards and was poised to release over 114 public artworks on the city when NPA responded by reposting their illegal content and patrolling the streets for our participants. The second project resulted in the arrest of 5 individuals. All of the arrested have had their cases dismissed and locked because NPA failed to sign the depositions, preferring to sweep the controversy under the rug as quickly as possible.
If I could just repeat myself a little bit:
Public spaces are public property. We all modify our environment by living in it. The sounds and smells and rhythms of the neighborhood are an organic reflection of its occupants. Putting up posters is just like trimming the hedges or mowing the lawn.
…It really actually irritates me quite a bit that commercial messages are seen as more legitimate uses of public space than artistic expression. I cannot just put my art up on the side of a building and expect it to remain. But if I were to post a commercial of some sort, people see it as normal and nobody even blinks.
When I go on an adventure wearing my safari hat / fake moustache outfit, the most common question I get asked is “Who are you working for?” The assumption is that we are all self-interested consumers, and that our actions are more or less directed by capitalism. When you start doing things that do not revolve around the exchange of money, a lot of people have trouble orienting onto it. Many are not used to thinking in non-commercial terms. They are used to having conversations where the subtext is money – what they did to earn it, how they spent it, why they need it… They tend to think of entertainment in terms of products or services — something to be consumed, not a playful interactive process. Their vocabulary of Fun has atrophied.
When I see something that clearly comes from outside of capitalism, I find it incredibly refreshing. It’s a signal that you don’t have to keep running around like a stressed out cash monkey. If you’re poor, you can orient yourself onto different rewards than money – and this can INSTANTLY transform your entire reality tunnel. Suddenly you’re not on the bottom rung anymore, you’re one of the only people on this sad rock who’s enjoying the ride.
Hey now hey now. Nothing begins like that, no song no nothing. Not a poem that is *known* or a book or a play or a movie but hey now now. The cities grow smaller with each and every passing day as they grow larger and more people come to the city, it’s always the same people that will settle for what everyone else is so as its form expands, its spirit diminishes. Where did we leave off when we forgot how to sing and dance, what happened to the diary we used to have but have no more, where did it disappear into nothingness, this us. When did you stop listening to what you did before you were 23 and what did you listen to, what do you listen to now? Can you watch inside your mind an argument with your parent and can you understand the parent?
nd we are in a world of science now, everything is being analyzed, perhaps latest of all, the very food we eat. There’s a movie called 
It flows and it ebbs, the river. We’ve been watching it for days now and we sit here, each and everyone with us collecting inspiration from the environment and everyone else, an acid dream coming through over two weeks as something new is born, a concept that encompasses all parts and thoughts of life, a package for everything for you in your life as we sat there and watched the river flow and ebb and we dreamt it at our stations and we saw it from within, it was only us there and the river, nothing caught in a twilight darkness, we were gray tainted men, tainted by civilization we appreciated nature in a professional sense, each with our profession and we changed.
I think there is hope in trying to teach people how to operate their brains.
on 
on