A while back, I heard about a big yarn bombing project in New Zealand. A knitter calling herself Knitty Graffity was asking for pieces to put on the railing around the wharf in Auckland for the Rugby World Cup which is being held there.
Here's a link to an article about it: http://www.nzherald.co.nz/lifestyle/news/article.cfm?c_id=6&objectid=10750575
Be sure to watch this video. http://www.localist.co.nz/milfordtakapunadevonport/articles/devonport-wharf-gets-woolly Our piece (black with colored flowers) is first visible at :19. There's a close-up of it not long after. Starting at :41 it's on the screen for about 10 seconds while being sewn onto the pole. Very cool.
You can read more about the project at Knitty Graffity's blog: http://knittygraffity.blogspot.com/