Well, there is the Classic-Castle Calendar Contest
Also, and I don't follow the day-to-day, but if you are involved in the LCC it looks like there are a couple of local challenges going on right now. I'm sure there is something similar in the Guilds of Historica over on Eurobricks as well.
It's always good to check the LEGO Contest Network
on Flickr. They have a thread where people can post announcements of any new LEGO contests.
There was a Tolkien vig contest on Flickr, that just ended