Do you have an old LCD monitor at home? You can turn it into a "spy" monitor. While everybody sees it as a monitor with white screen, you will have special "magic" glasses to make it work. Here is an instruction on how to make a privacy monitor out of an LCD monitor.
Don't forget to watch video with this awesome creation.
You’ll need an LCD monitor, old glasses (disposable 3D glasses or sunglasses are fine), paper cutter, screwdriver, paper towels, superglue and paint thinner.
Step 1. LCD Monitor
Find an old monitor to work with.