Step 1Cook the sausage in a large skillet over medium heat until lightly browned, stirring to keep crumbly, about 5 minutes. Pour off the excess fat, add the beef and cook, stirring, until browned, another 5 minutes. Stir in the garlic, onion and celery and cook until the vegetables are tender but not browned, 10 minutes. Stir in the tomatoes, corn, salt to taste and chili powder and simmer about 15 minutes. Slowly stir in the cornmeal and cook until thickened, 1 minute. Stir in the olives.
Step 2Heat the oven to 350 degrees.
Step 3Turn the mixture into a greased 2-quart casserole and top with the Jack and Cheddar cheeses. Bake until the cheeses have melted and the pie is bubbling, 45 minutes.