Cowdung Slurry

Thank god I've never seen it on a menu. Nevertheless, it may the solution to India's energy needs:

"If every village (of which we have 600,270) has 50 farmer families who maintain just two bullocks and four cows each, the cowdung of these animals can produce enough methane gas to take care of country's entire energy needs"

Times of India, 8 December, 2004