These are all wonderful suggestions - I like the Christmas tree idea!
One more thought I have, is please don't let your cats have Christmas ribbon. My kitten bit off a piece of nylon open-weave 1/2" ribbon and swallowed it. It's like velcro on their rough tongues! Luckily, that's all she swallowed, and I was able to give her some olive oil. She passed it that night.
But, a cat can swallow lots of ribbon - it just keeps on going down.