MATE is a fork of GNOME-2. You can read more about it here. Screenshots: here. The mechanism to be followed to install MATE is explained at: http://wiki.mate-desktop.org/download. I will reiterate it here so that it would be useful.
# Add one of the following repos to /etc/apt/sources.list. Note that 'add-apt-repository' is a link # to 'apt-add-repository' which is part of the 'python-software-properties' package. sudo add-apt-repository "deb http://packages.mate-desktop.org/repo/ubuntu quantal main"; sudo add-apt-repository "deb http://repo.mate-desktop.org/ubuntu quantal main"; # In case 'add-apt-repository' is not available in your system, you can consider # editing the /etc/apt/sources.list using a text editor and add one of the below lines. deb http://packages.mate-desktop.org/repo/ubuntu quantal main deb http://repo.mate-desktop.org/ubuntu quantal main # Execute the below commands to install MATE. sudo apt-get update sudo apt-get install mate-archive-keyring sudo apt-get update # Install the base package. sudo apt-get install mate-core # Install additional packages. sudo apt-get install mate-desktop-environment