Have lots of activities and things for the students, parents and teachers to do. Bring lots of food so nobody will be hungry at the end of the night. You can have a lot of fun games such as pin the nose on the snowman, pin the nose on the reindeer for the students and even the parents or teachers. Introducing and having a secret Santa is also something that would make the party interesting and at least everybody gets a gift. Nobody would leave empty handed.

I find a hip flask works well..........

Talent show. Chinese love it on holidays, completely forget about gawking over the foreigner, and I can just descretely slip out into the alley with a few beers.

Best Christmas in China so far. Only one person asked me why my nose was so big.

kchur is right, a Chinese "party" is more like a talent show with funny games mixed in. They seem to really enjoy it, so if you want the party to go smoothly, it may take some planning, but then it's easy while the party is going on. I think perhaps you waited too long to ask this question, as Christmas is tomorrow, and I don't know if you could throw it together quickly enough. Basically, they don't want to socialize, they want to be entertained, so having snacks and music in the background won't cut it.

Do not include a Nativity Scene....

dance and loud music, teach them moon walking, if it catches on , think how funny it will be if all of china moon walks every where they go.