The Team Fortress 2 Blog has an update breathlessly hyping something, without giving the slightest hint at what it might be. Something about distant rumblings, so start to get yourself all worked up if you are so inspired, though if Valve Time can impact firm announcements, there's no telling what effect it can have on such vagaries. To add some calories to the post, they do make note of the Polycount Contest and the new Official TF2 Wiki that's an outgrowth of the unofficial TF2 wiki.