What my friends and I did at easter was carry a person dressed as the easter bunny on a cross, through an Xtian parade. Because nothing happened as a result of it, why not do it again at christmas but with santa. If enough people do this at Xmas celebrations it would look cool.
Or (I know its been done) sneak into council offices and replace their answerphone tapes with Echonian Keys or Communist manifesto on cassette.
When the Gap stores ran a window dressing for the "White T-Shirt -perfect for everyone" we made 8.5" X 11" stickers with "White Culture- perfect for everyone" on them. Then we plastered the store front with them.