in terminal type these commands
sudo add-apt-repository ppa:gnome3-team/gnome3
sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get install gnome-shell
Afterward go into your login screen and there should be a box saying Ubuntu scroll down on it and pick Gnome.
(NOTE do not have system programs or apps running it will cause install to fail.)
I tried this out works perfectly.