I just started weight watchers today, and although it is a funny time to start a diet, there is no time like the present. I'm in the same position with work parties and of course there is christmas day itself.
For the work parties it's vodka and diet coke which is only one point and during the day i am going to eat loads of zero point soup, which will then leave 25 points to indulge in food and drink for the evening.
As for Christmas day, i'm going to ensure that i save four points a day on that week (sat - sun) and also try and exercise to earn 12 points in which i can indulge. Hopefully, i won't gain too much.