Here's a trick that'll stop opponents stealing sneaky glances at your screen during LAN matches. Instructables (opens in new tab) have a funky little monitor hack that'll make it show an apparently blank white screen, unless you're wearing polarised glasses, in which case the real image is suddenly revealed. If you want maximum privacy for your desktop screen, you will need a spare LCD monitor, one that you don't mind never having working normally again, and some sharp tools for some rather invasive screen surgery.
The idea is simple - you just remove the polarising film from the panel itself and inserting that into a pair of glasses - 3D cinema goggles will do nicely. There are many times I can think where this would come in handy. I remember one press unveiling where the company's US PR was sat in front of me writing derogatory things about the CEO's onstage performance to a buddy on MSN. My friend live-blogged his entire spiel. I bet he'll have been hacking at his laptop screen after seeing this. Also, if you're a spy. You're welcome, Mi5.
Still, if you've got an old screen gathering dust up in the attic and a penchant for a little light hackery, it's worth giving it a go. I'm certainly going to be taking a screwdriver to some of the old screens in the office kit cupboard. Total freedom to procrastinate - a dangerous development.