I am trying to find a way to "harden" my felted buttons. I found a pretty neat site on how to make some homemade plastics with stuff found around the house.
I want to try the milk and the lemon ones. I don't think I will have access to the glycerin to try to potato one but that looks really fun and with my knowledge of biochemistry, I think it would be pretty strong.
Also, there is an artist making bowls out of vegetables. He uses some sort of "proprietary drying and forming technique" to actually make bowls out of carrots and some other vegetables. http://www.inhabitat.com/2009/07/30/edible-art-biodegradable-bowls-made-from-vegetables/
Even cooler then those, there is a race car made of vegetables that runs on chocolate byproducts! It can go up to 135 miles per hour (whoa!). http://www.fastcompany.com/blog/ariel-schwartz/sustainability/race-car-made-vegetables-runs-chocolate