On Ubuntu 11.04 Natty Narwhal, we all tried Unity before. How about Gnome Shell 3 on Ubuntu? It is possible? But it is possible to install Gnome 3 on Ubuntu 11.04 (Natty Narwhal). In the matter of fact it is very simple to do so.
Gnome 3 Installation
Open up the terminal and type following commands:
$ sudo add-apt-repository ppa:gnome3-team/gnome3
$ sudo apt-get update
$ sudo apt-get dist-upgrade
$ sudo apt-get install gnome-shell
If you like Gnome 3 instead, you can add this command at your startup “gnome-shell –replace”.