UPDATE:
Game hosting is back online. The lobby chat isn't currently hooked up yet, so when you log in it will stay on the twitter feed tab. If you're having issues with OCTGN not loading, then go to http://www.octgn.net/Home/GetOctgn and install the latest version.
Please feel free to use our http://gitter.im/Octgn/General community chat as a temporary chat lobby until we can get the built-in chat working again.
Thanks everyone for your patience!