Graffiti is the ultimate and the original mash-up. Street artists using paint, canvas, and other things to enhance or remix a space. An interesting project that has been around in nyc is the bubble project. Ji-lee started the bubble project in 2001 after a career at an ad shop as an art director. He was fed up giving the public ads from large corporations that were propogating messages solely for profit. Sounds like a mid-lifer to me hmmm? Anyways he went about to create bubbles that could be stuck on art, posters, walls anything. He would come back a couple days later and photograph the results. Now he has published a book. Very simple concept, great idea to publish the book. These bubbles really are great catalysts, having seen quite a few on the LES. I had this idea a while ago, but never did anything with it nor did i have the visions for it Ji Lee did. His site is a great collections of public soundbites in the bubble form. Check it out.