This Mac tip is provided by Mark Greentree and was originally posted on Mark’s blog – Everyday Mac Support. For more of Mark’s tips visit his site, follow him on Twitter, or browse his archive of posts here.
Did you know you can reduced the brightness of your display to zero by simply clicking the following keys: Control + Shift + Eject.
To bring your display back to normal simply move your mouse or click a key.
This keyboard shortcut also works in Mac OS X Snow Leopard.
I use this method daily as I use an iMac and don’t wish to put the computer to sleep. By doing this you can reduce the running costs of your Mac.