Vik Muniz is a Brazilian born, New York based artist who experiments with media. His works are fleeting and consist of objects arranged to make an image, he then photographs the arrangement resulting in the final piece. He made two detailed replicas of Leonardo da Vinci's Mona Lisa: one out of jelly and the other out of peanut butter. He has also worked in sugar, wire, thread, and Bosco Chocolate Syrup, out of which he produced a recreation of Leonardo's Last Supper.
More recently he has been creating larger-scale works, such as pictures carved into the earth (geoglyphs) or made of huge piles of junk. For his "Pictures of Clouds" series, he had a skywriter draw cartoon outlines of clouds in the sky.
You can visit his offical web site here.