The challenge is called "Broken Heart Challenge". I haven't been able to find out more than that, but gauging from everyone's' pictures, I'm on the right track. You can see some progress pictures here from the other Art Doll Only artists: http://artdollsonly.ning.com/photo/photo/search?q=broken+heart
So far my doll is about 13 inches long, 8 inches tall (when sitting) and 4 inches wide. She has no arms, hair, lips, teeth or clothing yet, but they are coming along. I see some sort of skirt with crinoline and some crazy sort of afro hair thing going on. The arms will probably be more scarf-like than not (holding a heart? or holding a mangles heart? I don't know yet.) and the teeth will be in homage to the killer bunny from Monty Python's Holy Grail. She should be awesome.