A gray version of the Ubuntu default Light Themes (Ambiance & Radiance).
I just modified the original Radiance theme to make ir gray instead the original light brow. The original theme is designed by Canonical.
Tested on Ubuntu 13.10 only. Report any ideia and bugs to make ir better :)
Download this repository and move it to /usr/share/themes/ and select the theme (I recommend Ubuntu Tweak or Unity Tweak Tools)
Thanks.