First off, what about the lowly and ubiquitous plastic bag? Combined with some tape, an exacto knife, and a subway grate, Joshua Allen Harris has used them to construct some pretty nifty creations that have a nice kinetic element through the use of wind generated by passing subways.
Vik Muniz is a Brazilian artist now living in New York. His practice has ranged widely, but much of his work has centered around creating images using unconventional materials such as spaghetti, sugar or thread. He has a website, but there's a pretty interesting video of him on TED that's worth watching if you have a few minutes:
Finally, I'd like to mostly save "green" and "eco" art for another post, but sometimes there's some crossover and really I couldn't resist including one here that is both low tech and, some may say, eco-minded. Mainly, I just like how the artist, Edina Tokodi, uses the oft overlooked and non-toxic material of moss to take advantage of some locations that most would consider marginal at best.
