Hi storynanny:
I think the key is 'a creative teacher' - I fear my DDs (now Y4 & Y6) have all the way through had literally the last month of autumn term at school 'off'. I'd say maybe half the numeracy/ literacy hours occurred and basically they had one long party.
The Christmas 'production' at our school is really that - I'd say there's as much work put into it as the one year's run up to DD1's ballet class performance at the end of year 'show'. It's a 2 hour show, with costumes, dance numbers, lines read (written by teachers not pupils), etc... It truly is not a 'mere' nativity and a few carols.
Making a giant tree out of cardboard & painting it & decorating it with tensil for stage setting may involve maths (if creative) storynanny - but took DD1 & 3 classmates 3 full school days. Kind of wondered why they couldn't just move one of the class trees (of similar size) into the hall on the day. KS2 upper also get dragged into setting up the Christmas fair and clearing away afterwards. Y6 frequently are asked to help take down decorations on last day of term.
Our Christmas play will be next week. The children will have Christmas parties, the choir will be out of school to perform at local hospice & old folks home, there will be a Christmas games session in the hall, and I believe they expect father Christmas at some point. All classes go out at some point and sing to other classes/ HT. There are several extra assemblies to teach about advent/ Jesus' birth. (Hannakah, by the way, hasn't had a look in - as it the case with many other religious festivals this time of year).
I can't complain - it is tremendous fun for the kids but this and 3-4 days of DVD watching/ bring in a game from home in the last week + big church service taking most of last day - all means not a lot of school work is done for about 1 full calendar month. I try to make up for it by upping my game at home from about mid-November and doing a bit extra after a few days off for Christmas.