Every day until Christmas, a new Hubble image will be featured until Christmas.
Also, Emily Lakdawalla has an advent calendar featuring objects from the solar system on The Planetary Society Blog.
And there is yet another on the Zooniverse website, http://www.zooniverse.org/advent
I think these are fantastic – they are a great way of getting people interested in science and astronomy. And by showing a glimpse of the marvels of the universe, they can maybe take our minds off spending money for a short time.
More wonderful photos which would have made a great advent calendar are entrants in the National Geographic Photography Competition 2010 (some of which are featured here on the Big Picture). The winner will be announced before Christmas…
Hopefully next year we will see more scientific countdowns to Christmas! It can’t just be astronomy with all the exciting pictures.