Cut a thin slice of peel from the bottom of each orange so it will not roll. Slice off the top 1/3 of each orange. Scoop out the inside with the knife and grapefruit spoon. Put the pulp and juice (minus seeds) into the blender. Add container of yogurt and blend well. Decorate orange like a Jack-O-Lantern. Cut a hole in the "cap" and insert a straw. Pour drink from blender into Jack-O-Lantern cups and serve. Enjoy!