Hello Linux Geeksters. As you may know, the Ubuntu developers are creating a special Ubuntu 14.10 flavor, that uses Mir and Unity 8 as default. While Unity 8 and Mir are already running by default on Ubuntu Touch, the mobile version of Ubuntu, they will land on the desktop version starting with Ubuntu 16.04 LTS.
Also worth mentioning, Mark Shuttleworth has recently announced that both Nvidia and AMD will create GPU drivers with official Mir support.
A special PPA containing GTK+ applications with support for Mir has been recently created, enabling the users to test the new file manager, browser, image viewer and other apps specially developed for Mir and currently used only on Ubuntu Touch. For now, only Gedit, Gnome Calculator and Simple Scan are available for Mir, but new apps will join this list soon.
Also, a demo video of GTK+ apps running on Mir has been released:
If you are using one of the Ubuntu 14.10 daily build images, you can toy around with the GTK+ apps over Mir yourself. All you have to do is add the needed ppa to your system, update the local repository index and perform a system upgrade:
$ sudo apt-add-repository ppa:ubuntu-desktop/gtk-mir
$ sudo apt-get update
$ sudo apt-get upgrade