Because desktop environments such as Cinnamon, Mate or LXDE are not available in Pinguy 12.04, I have chosen Razor-QT .

Razor-QT is an easy to use fast desktop environment, based on the QT technologies.
So, installing Razor-QT on Pinguy 12.04:
Step 1. Adding the Razor-QT PPA:
$ sudo add-apt-repository ppa:razor-qt
Step 2. Update system:
$ sudo apt-get update
Step 3. Install Razor-QT:
$ sudo apt-get install razorqt
This is it, reboot and choose Razor-QT from the grafical menu.