here is a handy way to decline holiday parties:
I am somewhat sorry to say that I will be unable to attend your haute
 holiday gala. I will be climbing Mt. Kilimanjaro and thus compelled to 
miss out on the warmth and joy that always fill your parties. Once the 
holidays are past I hope to have a good long visit with you and find out
 all the party highlights. Please give my sunniest, "Hi there and 
hello," to your party guests. My best wishes for a happy and utterly 
Norman Rockwellian holiday.
Remember to wear your mittens.