Here's a quick DIY project I wrote for Create and Craft recently - mason jar lid ornaments. I have plenty of lids lying around in drawers and boxes, leftover from other craft projects, and I decided to put them to good use by turning them into tree ornaments.
Create and Craft sell all the supplies you need to make these. Go over to their blog to read the full tutorial here. There are countless ways you could personalize these ornaments.