Grocery paper bags can make great hats. Depending on the size of the bag and the size of the head that you are fitting it for, you can either fit the bag on your head as it is or you can cut out the shape of hat you want, make a second cutout that is exactly the same (for the front and the back of the hat) and then use yarn and a large sewing needle or glue to adhere the two sides together. You can decorate the hat however you want. One suggestion is to add streamers to the top to make a princess hat or a feather to make a Peter Pan hat.