Here's a little(big) piece which consists entirely of trash collected from numerous parks created by Gregory Euclide. I dont know how who collected the trash but I'm guessing it wasn't that pleasant...unless they were into it....or payed...probably both. Check out the link for more pictures of this DIY art and let it inspire you to save your trash and try to 1up this guy.
http://www.designboom.com/weblog/cat/10/view/19194/gregory-euclide-microcosmic-world-made-from-park-trash.html
http://www.designboom.com/weblog/cat/10/view/19194/gregory-euclide-microcosmic-world-made-from-park-trash.html