One of my gripes with openbox is the process of getting aero snap style window placement via keyboard shortcuts working nicely. A window manager independent solution I stumbled across that has been working nicely for me is QuickTile. I spent some time today looking for it. In anticipation of that happening again in the future, this article will live on.
You can find out all the gory details (setup, configuration etc) at the project's GitHub page.
Have fun with your windows!