Each year agencies use their creativity to spread a little holiday cheer. This is a list of what they did, via Brandrepublic.
AKQA (microwaves)
Grey London (they went green)
Albion (queen speech)
Lowe (employee tree)
MCBD (monster greeting)
McCann Erickson (animation)
Proximity (save children)
RKCR & Saint (winehouse spoof)
St Luke’s (snowball fight)