Clear-Lux is an open source package that contains themes for GTK2, GTK3, Cinnamon and GNOME Shell. Each theme has three different colors: green, blue and yellow.
How to install for GTK3 and GNOME-Shell?
For detailed installation instructions please see the following tutorial created by Softpedia: http://news.softpedia.com/news/How-to-Install-GNOME-Themes-in-Ubuntu-11-10-231213.shtml
How to install for GTK2?
· Right click on your desktop and select Change Desktop Background
· Click on the first tab: Theme
· Drag and drop the theme's archive in the Appearance Preferences window.
· If everything is OK, you will receive a confirmation message and you can activate the theme just by clicking on it.
· GNOME Shell