Pause Me
Pause Me helps you to apply the 20-20-20 rule rule to prevent eyestrain while working in front of a screen.
It is a small Windows .NET application that hides in the taskbar. Every 20 minutes a pause overlay will be displayed in front of your currently running applications. The overlay shows a countdown timer and will hide itself as soon as the 20 seconds have passed.
In case you would like to skip a pause you can hide the overlay by double clicking onto it.
To get Pause Me either download it or build it from source.
Pause Me is Beerware.