Cinnamon is a Gnome-Shell desktop fork. It is not strictly a Gnome-2 interface, although the developers aims are laudable – to produce a simpler more traditional desktop interface. Development seems to be rapid. It is usable and certainly fun to play with with a growing number of extensions to install to extend the base installation. Here is the guide to install cinnamon desktop on Ubuntu 11.10.
Open Terminal (Ctrl + Alt + T).
raj@geeksite~/$ sudo add-apt-repository ppa:merlwiz79/cinnamon-ppa
Update the system repository.
raj@geeksite~/$ sudo apt-get update
Install Cinnamon desktop.
raj@geeksite~/$ sudo apt-get install cinnamon-session cinnamon
Once installed, logout and select cinnamon by clicking on gear icon in login page.
Now you should get the following desktop.