There's also PoserFreaks, a German site requiring registration. The whole advent calendar is supposed to be available till the 30th.
www.poser-freaks.de/adventskalender.php

3DArena, which was somewhat disappointing for a while, suddenly has a whole pile of free items, but I don't know if there's a time limit
3-darena.com/index.php

My visual indexes of Poser content are at http://www.sharecg.com/pf/rgagnon