Install Orion GTK3 Themes on Ubuntu 12.04/11.10/Linux Mint

Install Orion GTK3 Themes on Ubuntu 12.04 Precise Pangolin/Ubuntu 11.10 Oneiric Ocelot/Linux Mint (GTK3)

Orion is a modern light theme for Gnome. It supports Gnome Shell, Unity, XFCE and Openbox. The theme is compatible with the latest GTK 3.4 and uses the Unico engine. It also includes a GTK 2.0 theme using Murrine engine.

To Install Orion on Ubuntu/Linux Mint open Terminal (Press Ctrl+Alt+T) and copy the following commands in the Terminal:

Terminal Commands:
sudo add-apt-repository ppa:satyajit-happy/themes
sudo apt-get update
sudo apt-get install orion-gtk-theme

Enjoy

Source: satya_page_DevianArt