I blogged earlier about decorating hte Park Island for the winter - made it snow, covered the ground with snow, put in some dead/wintery trees.
I went over to the many Rezzable islands the other day - that's a subject for another post (what are they doing with all those islands - urban sims, vampire castles - all for RPGs?). They have the Greenies house. And now they have an island with a huge Greenies Christmas tree. Here are two pics.