This is a really good idea: using gorgeous Hubble images to make cards for the season. The site has instructions on how to print them, and of course links to the images as well.
I have to say, I think my favorite is this one:
The picture is from the Galactic center in Sagittarius, where stars are plentiful. I recognized it immediately (I'm a dork), but the idea of using it for ornaments was pretty clever and very funny.
The most ironic one is this one:
I hate to break it to my friends at Hubble, but Mars is the god of war. Maybe a hawk would have been a better choice for the silhouette.
Or maybe it's all part of the subtle War on Christmas: all the cards say "holiday" and "season", and not Christmas. Maybe they should have a Hubble picture of the Star of Bethlehem?