Put together a nativity scene on the blackboard as you sing Christmas songs. Print and cut out the document below. Write a song name and page number on the back of each one (my suggestions are listed). One by one, have the children choose a piece to place on the board. Sing the songs as you go.
If your kids don't know enough songs, you can bring Hymnals in for the older children. Ask younger children to sing "ooooh," like an angel if they don't know the words. Many children will know the words from home and almost all of the children will recognize the melodies enough to sing along.
The First Noel, Hymns 213
Away in a Manger 42
With Wondering Awe Hymns #210
Once Within a Lowly Stable #41
Stars Were Gleaming #37
Angels We Have Heard on High, Hymns #203
When Joseph Went to Bethlehem #38
Shepherd's Carol #40
NOTE: By request, I've added a male angel (I don't know why I didn't have any?). Unfortunately, I didn't have time to add him to the document. If you want to use him, just right click on the image above, copy and paste into a document, then size as necessary.