Here is a guide to install the Cinnamon desktop on Ubuntu 11.10. You can install Cinnamon desktop by adding the merlwiz79 PPA for the Cinnamon Desktop.
To add the PPA and install Cinnamon Desktop open a terminal window (press Ctrl+Alt+T) and copy+paste the following lines:
sudo add-apt-repository ppa:merlwiz79/cinnamon-ppa
sudo apt-get update
sudo apt-get install cinnamon-session cinnamon
When the Cinnamon desktop is installed you can close the terminal window and logout and Change the session to Cinnamon and log in again.
Cinnamon LinuxMint Homepage
With Gnome 2 no longer an option we lost one of the most important upstream components our Linux Mint desktop was based on. Our entire focus shifted from innovating on the desktop, to patching existing alternatives such as Gnome Shell. We used MATE and MGSE to provide an easier transition away from Gnome 2, but without being able to truly offer an alternative that was better than Gnome 2. Both MATE and Gnome Shell are promising projects but MATE’s ultimate goal is to replicate Gnome 2 using GTK+ and Gnome Shell doesn’t provide what we need in a desktop and is going in a direction we do not want to follow. So for these reasons we’re designing a new desktop called Cinnamon, which leverages new technology and implements our vision.
Read more about Cinnamon desktop.