This metacity theme was initially inspired in the Dark Ugly Case metacity. It fits better (in my opinion) with dark gtk themes and it uses the dark[normal] colour of gtk themes to produce the case around the window. The name is somehow inspired in the design of the buttons. Like in Adwaita, all its elements (including buttons) are direcly drawn in the xml file (i.e., the theme is composed by a single metacity-1.xml file).
To install, just download the .zip file, uncompress it and copy the contents to /usr/share/themes/. After that, the Radionactive theme should appear as an option on the gnome-tweak-tool (tab Theme->Window Theme).
For an easier installation, just COPY AND PASTE (!after checking the commands!) the following commands into the terminal:
sudo cp -r Radionactive/ /usr/share/themes/
rm -r Radionactive/
Please note that I only tested the theme on Gnome3, but it should work on Gnome2 also. The theme should then appear as an option for the windows on the appearances settings of Gnome2.
Hope you enjoy it.