Bashiok has announced that the elemental invasion boss portals are open in the capital cities "permanently" (which means they'll likely be going away when the patch hits tomorrow morning). Now is your chance to farm any additional items you want from those bosses or grind out a ton of easy justice points.
The blue announcement is as follows:
Due to your valiant efforts in protecting the key invasion cities, the four boss portals are now 'permanently' open. If you need anything from inside the portals, or maybe you dropped your keys in there, now is the time to go through and get them.
Initial reports from shaman in the area that were available at time of publishing suggest that this is hinting at something far more sinister. One such shaman, a one 'Krunkmaster' from Proudmoore was quoted as saying "This is hinting at something far more sinister."