Christmas ornaments made from paper bowls are inexpensive, don't break, and offer plenty of room for everyone to fully express their creativity. There is no limit to the ways in which the ornaments can be decorated: you can use different types of paint, and add beads, glitter, etc.
Also have a look at my other Christmas Ornament Craft. When a whole class makes Christmas ornaments, you get a very special Christmas tree!
The document contains patterns for the collar and ring that allow you to hang the bell in the tree.