Buy a couple of turkey legs, which are usually inexpensive, and make your stock in the same way you'd make chicken stock: with carrots, onions, celery, parsley, bay leaves and peppercorns. Strain, add white wine or dry sherry, then reduce. Thaw it out on Christmas Eve, then add the juices from your cooked turkey on the day. This one's a real time-saver!
Get the recipe for gravy here