While not exactly edible, Java Log comes from coffee and is combustible. It is made by a company that develops technologies and products which "close the loop" in production and consumption, by reusing waste products. The first is basically a Duraflame, made from spent coffee grounds.
It's less toxic, and might even smell like a fresh cuppa. The perfect house-gift for your under-caffeinated holiday host or your pyromaniacal, ambiance-setting boyfriend.