Short of carving up a piece of citrus fruit and jury-rigging it with moveable hands and gears, you're unlikely to find a greener timekeeper than this wall-mounted Juice Clock. Its bumpy face, complete with "seed" holes, would look good enough to eat if it weren't made from recycled HDPE plastic (the same stuff used to make detergent bottles).
In keeping with the juice theme, batteries are included, and it's available in orange (pictured), lemon or grapefruit: $45 from re:modern.
