Since it is being held in a public place you should have quieter games so as not to disturb other patrons. I would suggest that you have everyone form other words from Christmas Party and words related to your company such as Electronics or computers if that is what you sell. The winner(s) can get a silly prize. Provide paper and written instructions. I personally prefer a party where everyone mingles rather than being forced to play games. Are you sure that everyone wants to play games rather than just enjoy the season?