Use your initiative. If budgets are tight, there's no reason entertainments have to suffer. Imbue it with the right message, and people may even enjoy them more. Take Baldric in Blackadder's Christmas Carol: his nativity play has been adversely affected by the high infant mortality rates, so he has to find a replacement for the baby Jesus. He makes an unconventional choice, but it doesn't make it any less of a success. In fact it's such a hit the kids want to see how the replacement fares at Easter.
Include everyone. Not everybody is mad for Secret Santa antics; others will sit there at their desk happily pumping out Wham's Last Christmas on tinny PC speakers. Get the balance. The staff at The Office, the American version, suddenly find one colleague slapping a roadkill goose on the reception desk, and suggesting they should eat it. The team is divided over whether it's a suitable celebration, but the manager's decision keeps everyone happy. Almost.
Take it easy. People always get carried away at Christmas, and for many that's what it's all about these days. Follow the simple rules and you should be okay: keep your clothes on at the Christmas party, don't get physical with the boss and, as Richard E Grant is advised in Withnail and I, 'Don't mix your drinks!' He is drinking lighter fluid at the time. If you've reached that stage, it's time to go home.