When our kids were in high school, we cut WAY back during December. We just did the very CORE subjects, doing just the things that needed to be done in order to make progress during the year. That means we worked on math and foreign language every day, mostly. They loved reading, so nothing I could do would make them stop reading their beloved books. It was fun for them.
The entire month of December we did school for perhaps 3-4 hours a day. Like a public schools half-day, we crammed in all the core subjects into the morning, and took the rest of the day off. Math, foreign language, some science perhaps, so we wouldn't lose our place in the book, journal writing, and their reading. After that, they helped with holiday things. They wrote Christmas cards, composed a Christmas letter, went shopping, budgeted and bought gifts, helped with decorating, baking, and delivering gifts.
Most of the time, though, they just "did their own thing." I kept them away from computer games and the TV, so they entertained themselves in ways that didn't make them brain dead. I found out later that "doing your own thing" meant you were actually learning something too! They were reading, playing educational games, working on real projects. It was all learning, it just wasn't all book learning.
Think of December as a good time for them to work on their electives. Service projects or Occupational Education (even get a seasonal job, perhaps.) Or you could do what I did, and just let them do something that didn't include TV and video games.
Christmas was a huge stress to me as well. Perhaps because I had boys, but it seemed like EVERYTHING was my job - it was very overwhelming. Taking it a bit easy can save your sanity. Nothing good will happen if mom goes insane, you know!
A lot of people are getting REAL excited about the launch of our new e-book, "The Easy Truth About Homeschool Transcripts." We will be sending out additional emails to give more details on the book and the very special offers for our first purchasers! Lots to do between now and our December 12 launch!