A Better Aero Snap with Openbox

rc.xml

<!-- Window Tiling: Emulates Windows 7 Snap feature JASON CAVETT -->
<keybind key="W-Left">
  <action name="UnmaximizeFull"/>
  <action name="MaximizeVert"/>
  <action name="MoveResizeTo">
    <width>50%</width>
  </action>
  <action name="MoveToEdgeWest"/>
</keybind>
<keybind key="W-Right">
  <action name="UnmaximizeFull"/>
  <action name="MaximizeVert"/>
  <action name="MoveResizeTo">
    <width>50%</width>
  </action>
  <action name="MoveToEdgeEast"/>
</keybind>

works !