Transform Your Old Mac into a Second Screen
If you feel there’s no such thing as too much screen real estate, you might want to recycle your old Mac as a display for your laptop.
Popular Mechanics suggests downloading ScreenRecycler (there’s a gratis or $29 version) a driver that creates a virtual display that is then shared via VNC so you can multitask with two displays.
You can even use an old PC monitor (gasp!) for display as long as the main computer’s a Mac.
As someone who tends to keep old machines around long after they’re useful, I love this idea.
Anyone tried it?
Nicole Martinelli is a San Francisco native who has lived in Milan and Florence, Italy. She's written for Wired.com, The New York Times and Newsweek. You can find her on 
