on Planet Green!
I've long been an admirer of Chef Homaro Cantu of Moto in Chicago. You may know him as the guy who prints out edible menus each night. Challenges on the show have included making edible packing peanuts, then preparing tasting menus with them, and creating junk food out of granola bars and ugly green super food smoothies.
Everything they prepare on the show is tested both on the streets and in the restaurant, with the goal of creating delicious food that is somehow environmentally responsible. I have never had so much fun watching a cooking show!