The first thing you can do for a corporate Christmas activity is a secret Santa gift exchange. You can choose names in a function held after work hours and you can exchange the gifts at the corporate Christmas party. Set a limit that seems reasonable and ask everyone to stay within that limit to make sure it is a fun and fair gift exchange. You may want to keep the executives out of a secret Santa because it can be uncomfortable if the company receptionist has to give a gift to the president of the company. So keep the gift exchange among the employees and make sure management understands why. There is a pretty good chance that management will not mind.
Another idea is to have people bring in various Christmas treats leading up to the Christmas season. In many companies the Christmas and New Year’s seasons are times when many people take extended vacations. So to help lead up to that time you can designate maybe the last 12 days leading up to Christmas as days that certain people are to bring in treats. Leave a sign up sheet in the lunch room and ask people to volunteer to bring in something. Everyone likes to eat sweets and treats and sometimes you find someone who makes something you have never had before and it winds up being the best Christmas treat you have ever had.
Many corporate Christmas functions also center around charity. Regardless of your feelings on Christmas everyone can agree that giving to charity is worthwhile. Many companies reach out through the local Salvation Army chapter and adopt a needy family for Christmas. The office will be told how many people are in the family and if they are adult or child and male or female. The company is never told who the family is they are just told what the family needs. Then the office puts together a fund and purchases the things that the Salvation Army says the family needs. The Salvation Army then brings those gifts and other things, like sometimes they donate food, to the needy family. Sometimes the Salvation Army will tell the needy family which company made the donations and sometimes they do not but either way it is a gesture that helps make a family’s Christmas brighter and can bring an office together.