I have a custom developed administrative system, which customer service etc are using allmost throughout the day. The interface is simple, although a lot of functionality exists, but the look is quite dull and boring as of now and my design skills are not my strong side.

Do you have any hints/tips about good looking open source administrative templates, that could be adapted to the system? Wordpress admin-stuff is quite good, but the menu is not very good. I also like letsfreckles layout.