This theme is based on Marika's Black Grass Openbox theme, which you can find here:

http://box-look.org/content/show.php/Black+Grass?content=103023

My version has a few usability tweaks:
- disabled menu items will now show up darker instead of lighter than enabled menu items (this can be quite confusing) - see screenshot #2
- the OSD dialog shown when you change virtual desktop will now visually display what desktop you are on. The active desktop will be black, the inactive ones will have the same green colour as the title background of your Openbox root menu - see screenshot #3