Another fun ornament craft I found was making model magic ornaments. I haven't used model magic much if ever before, but it did end up making fun ornaments.
I got one package of white model magic, but other christmas or holiday colors would be great too. I rolled it out on my cutting mat and used some christmas cookie cutters to cut out shapes. To have a place to hang them from, I used the end of a straw to make little holes in the top that I could pass twine or ribbons through.
The drying time for model magic is a bit long at 24-48 hours, and I had to sit them up high so that curious kitties couldn't leave model magic footprints behind.
Since I made a few snowmen, I used some acrylic paint to give them some faces, buttons, and scarves. I also did a little paint doodle on another ornament just to add some color. The model magic blends pretty well according to the package directions, so I think it could be neat to do some color blending and have a striped or marble effect dried into the ornaments.