http://ubuntuportal.com/2012/04/how-to-install-mate-desktop-in-ubuntu-12-04ubuntu-11-10.html. This tutorial explains how to install the MATE desktop on Ubuntu 12.04 and 12.10. This desktop is an amazing desktop if you are familiar with the Gnome 2.32.2 desktop that was used in previous releases of the Ubuntu distribution. As you can see in the shot to the right; this desktop was very good before it went crazy in the Gnome 3 release.
I just found out that there are ISO images available for the Ubuntu 13.04 Raring Ringtail distribution. Download links below.
PC x86 desktop image: http://cdimage.ubuntu.com/daily-live/current/raring-desktop-i386.iso
PC X86_64 desktop image: http://cdimage.ubuntu.com/daily-live/current/raring-desktop-amd64.iso