Installing/Upgrade Gnome 3.8 on Ubuntu 12.04

First open ur terminal

1. sudo add-apt-repository ppa:gnome3-team/gnome3
2. sudo add-apt-repository ppa:ricotz/testing
3. sudo add-apt-repository ppa:ricotz/staging
4. sudo apt-get update && sudo apt-get upgrade
5. sudo apt-get install gdm gnome-shell gnome-tweak-tool
6. Reboot and type gnome-shell --version and WHOOPSSS u have gnome 3.8 on ur ubuntu 12.04 ;)