You may want to consider broadening your theme to "Holidays Around the World". Then "Christmas" can be a component but you can embrace other areas such as Hanukkah, Kwanza , Chinese New Year, Boxing Day. Ours was
Breakfast with Santa for years but evolved to
Holidays Around the World - still having Santa as an important feature.
It was a series of craft and activity tables, refreshments, pictures with Santa, (Christmas) karoke continuously on the cafeteria stage, and sometimes a service project like a canned food drive or creating festive decorated boxes (Boxing Day) to use as containers to hold gifts for an annual nursing home trip by some of students.
You might also want to search some of the old postings as I recall some good discussions on this in the past.
Here's a link
to one post from when I was involved.
For us it was a Saturday morning event in early December and a real favorite with the families. One "problem" we had each year was that we always had
too many volunteers. Not wanting to turn anyone away - ever - sometimes it required creativity on the part of the chair to actually find things for everyone to do. (This was the
only event for which that was a problem!)