Santa Hat Game
One way you can do that is play the 'hat game'. With the hat game you give everyone a Santa hat when they arrive. They don't cost much and they can be purchased for about $1 each. Everyone can go about his or her day wearing the hat to give the atmosphere a festive look, but that's not the main objective of the 'hat game'.
The main objective of the game is to 'lose the hat' because you don't want to be the last one wearing one! As people go about the day opening gifts, playing games with the kids, eating, chatting etc. there's bound to be at least one person who will forget to take it off and will be declared the loser!
Quess What's In The Sock Game
Another good game is called the 'guess the contents' game. What you will need is a pair of heavy-duty socks that come up to about your calf and then some Christmas related items. You'll want to have 2 of each item and you'll put 1 of each item in each sock. You could use things like candy, small ornaments, tape roll, pinecone, etc... Next you'll let each person feel the sock and tell them how many items are in the socks. The purpose of 2 socks is to make the game go faster but if the group is small 1 sock will do. Have each person write down what they think the contents of the sock are. The one who wins gets to keep the socks!
American Idol "Christmas Style"
If you have some people who like to be the center of attention in your group, you may opt to play a little game of "Christmas Idol". You will need to set up a couple of tables for the "judges" to sit and then let the performers take the floor and sing a Christmas song. Have them dress up for the part and have some fun with the song to make it more entertaining. To add a little twist to the judging you may want to let the kids judge the adults and visa versa if you have some kids who like to ham it up as well. For the adult winners you can give them a Christmas CD and for the kids some kind of toy or candy will always be a hit!
More Christmas Ideas:
Little Kids Christmas Crafts
The Ultimate Christmas Guide
Christmas & Advent Celebration For The Holidays Package