The code itself is a derivative of [Write a Screensaver that Actually Works](http://www.codeproject.com/Articles/14081/Write-a-Screensaver-that-Actually-Works),
There are programs out there (e.g. Pro Key Lock, Transparent Screen Lock) that can lock your computer's keyboard/mouse while still showing the running applications, which can be very useful.
However they rely on hacky techniques like intercepting Win32 Messages and they charge money.
Pro Key Lock, for instance, freaked out when I turned on Sticky Keys for my RSI and I had to forcefully reboot my computer.
After that, I felt there had to be a simpler way to do it that took advantage of Windows native lock screen abilities. So