MonitorSleep
A very simple Windows program that will put your monitors to sleep without putting Windows to sleep. I keep a shortcut to it on my desktop so I can easily switch off both my monitors. A simple mouse move or keystroke will wake the displays back up again. May not work with all monitors and cable types. (Try HDMI or Displayport if the VGA connection doesn't work).
A ready to run EXE file is provided in the PreBuilt directory. Just copy it to your desktop!