1. Use them as coasters... glue felt to the back and front so that you have instant coasters to protect your tables. Be sure to get fancy with the fronts. I made mine to look like poinsettias but warned people not to spill anything on them lol...
2. Need a little artwork for the wall? Cut up some of your favorite used Christmas cards and glue them to the cd. Hang with a ribbon. You could even do a series of Christmas cards to hang vertically in an forgotten corner. Brings a little unexpected Christmas cheer to the room. It also works very nicely for the bathroom. Yes, I'm into decorating every room for Christmas!
3. While on the topic of Christmas, you could hang some on the trees outside to catch the sunlight. they really dazzle in the sunlight and who says that you can't decorate without Christmas lights?
4. Put them under candles to prevent wax from accidently dribbling on your wooden tables. Leaving them unadorned beneath black and orange candles is especially effective for Halloween!
5. You can also melt the cds so that they form a cup. They are perfect for tea candles and seeing that it is for the holiday season, I would suggestion pine scented. Obviously, this is even better at protecting your table tops.
6. Make two room divider (suspended cds) that can be suspended on either side of the Christmas tree. The glowing lights reflected onto the suspended cds, will make the room almost magical. Or you could hang one room divider behind the tree. Allow two or three feet on either side for the Christmas tree glow.