This morning we were given a pleasantly early notice regarding tomorrow's maintenance downtime for North American and Oceanic realms. Realms will be going down at 3:00 AM PST, and are expected to be down until 11:00 AM PST at the earliest.
Though we haven't seen official word on the topic yet, it's expected that the next wing of Icecrown Citadel, the Plagueworks, will open tomorrow once realms come back online. This wing will include the bosses Rotface, Festergut, and Professor Putricide. Personally, I wouldn't be surprised if we also saw a minor bug fix patch tomorrow, but only time will tell.
If we hear anymore regarding either of those things throughout the day, we'll be sure to keep you updated.
Edit: I know how to use a calendar. Really. I do.