Sandwich Art by David Laferriere
It probably won't wind up in an art gallery but it gets points for creativity and dedication. Since 2008, David Laferriere has been doodling on his kid's sandwich bags with a Sharpie marker. He then takes a picture of the finished work and posts it on Flickr but his kids don't see the drawing until lunchtime.
The challenges are coming up with an idea and then drawing quickly and directly on the bag, every line counts.