Ours is a PTO Sponsored event that takes place on Saturday in mid-December, formerly known as "Breakfast with Santa". There are a combination of free and fee items. It lasts from 8:30-11:00. It's not intended to be a fundraiser, just to break even. Expenses are about $500.
There are tons of things you could do from crafts to stories to food. Your teachers will have lots of ideas/resources and you can draw on families that represent a certain culture to help host an activity.
In our case the event is held primarily in the cafeteria (which has a stage) and the adoining hallway. The room is set up with stations.
We always have:
1) Concessions - sell hot chocolate, juice, donuts.
2) Christmas Karoke - I'll admit ours are mostly Christmas songs like Jingle Bells, but you could sing anything anyone wanted. It's a blast, very high energy, gives the parents something to watch.
Additionally, we have a selection of the following so there are 5 or 6 activities. (They may very each year.)
Boxing Day - Our second grade has a field trip each December where they collect toiletries and small items, pack them in boxes, and visit a nursing home. Each resident gets at box. For our holiday party, we asked for donations (in advance) of shoe boxes and wrapping paper. At this station, children decorated the boxes - with paper, markers, yarn, sequins, whatever to be used later on the field trip. (Note lids needs to be decorated separately, so boxes can be filled later.) Also, some of the very young children didn't quite get the idea they were decorating the box for someone else and wouldn't be taking it home. But it worked well.
Chinese New Year - kids made and decorated a Chinese lantern.
Picture with Santa ($1.50) - have your picture taken with Santa. Instead of buying the cardboard frames, we had folded construction paper that the kids decorated and then the picture was placed inside with a glue stick. Note - if kids just wanted to talk to Santa or parents wanted to use their own camera, that was okay (no charge).
Christmas/Holiday/Happy New Year Cards for the armed service personnel stationed overseas. Kids make cards.
Hanukkah- I believe did either a craft of a game associated with "Spin The Dreidel"
Kwanzaa - I don't remember if we did this one. It may have been a short explanation followed by a word search puzzle.
Crafts - sometimes we also do winter crafts like making a snowflake out of popsicle sticks and adding glitter or making the woven placemats out of construction paper.
There are just a million things you can do. Have fun!