MATE, the “traditional desktop environment”, has been uploaded to the proposed repository of Ubuntu 14.04 Trusty Tahr. If all goes well and no package conflicts arise, then it will make it to the main repo soon.
However, the MATE-specific apps, like Caja file manager and Pluma text editor, have not yet been uploaded.
What is MATE?
MATE is a fork of GNOME 2 desktop environment, aiming to provide a traditional user interface that works fine with or without hardware acceleration and display compositing. It began where GNOME 2 left off, and most of its in-house apps are based on their GNOME 2 counterparts — for instance, Caja is based on Nautilus 2.x, Pluma on Gedit 2.x, and so on.
MATE is already available in the official repos of Fedora, Mint, Mageia and openSUSE.