iSpazz is a plugin for iTunes on OS X, controlling the MacBook Pro/PowerBook backlight keyboard and optionally the display backlight.
To use this yourself, download the plugin, uncompress it and copy it to Library/iTunes/iTunes Plug-ins in your home folder.
Pressing the “i” key toggles the display flicker. Use at your own risk.
Thanks go to apple4ever from the Mac Ach, Amit Singh, Marvis and Tommi Brem.
Oh, and before I forget: No warranty whatsoever. If the display flicker mode eventually kills your computer’s backlight, it’s not my problem - sorry.