I think when working in an agency everyone of us has faced that simple question that reads "what will we do for Christmas?". Although the main solution in the latest times has been uploading your face to customize some kind of animation i feel a bit tired of it, as only a few pieces have really succeeded (the famous Elf Yourself as one of the main examples)
So a few days ago i heard about this nice campaign called "Christmas lights"developed by Scholz&Volkmer; for Coke in Germany, in which you can use a mashup of Google Maps to zoom in until you find your friends' houses.
Then you can decorate their roofs with Christmas lightings, sending them the final composition to their email adresses. Simple and quite original, specially in these days.
ps: by the way, Ashley from Bannerblog spent some of his time collecting over 170 Christmas cards, as I read from my good friend Fer aka Grizzly.