OakRedditor's menu.xml

<?xml version='1.0' encoding='utf-8'?>
<ns0:openbox_menu xmlns:ns0="http://openbox.org/3.4/menu">
  <ns0:menu id="root-menu" label="Openbox 3">
    <ns0:menu id="applications" label="Applications" execute="xdg_menu --format openbox3-pipe --root-menu /etc/xdg/menus/arch-applications.menu" />
    <ns0:separator />
    <ns0:item label="Log Out">
      <ns0:action name="Exit">
        <ns0:prompt>yes</ns0:prompt>
      </ns0:action>
    </ns0:item>
    <menu id="menu-6249525" label="Power Settings">
      <item label="Shutdown">
        <action name="Execute">
          <execute>systemctl poweroff</execute>
        </action>
      </item>
      <item label="Reboot">
        <action name="Execute">
          <execute>systemctl reboot</execute>
        </action>
      </item>
      <item label="Sleep">
        <action name="Execute">
          <execute>systemctl suspend</execute>
        </action>
      </item>
    </menu>
  </ns0:menu>
</ns0:openbox_menu>