Skytopia has released SunsetScreen, a free tool for Windows XP and later which automatically reduces the glare on your screen at night.
In theory, reducing your exposure to blue light in the evenings may help avoid problems with melatonin production, and so give you a more restful sleep. But even if that doesn’t work, having the screen match your current lighting conditions could make your computer more comfortable to use.
F.lux does something very similar already, but SunsetScreen is much more configurable. You can set a precise sunrise time, the number of hours until sunset, and the hue, saturation and brightness for both your night and day colors.
This is more difficult to set up and maintain than f.lux, as you can’t just set a location and leave SunsetScreen to figure out sunrise and sunset times itself. But the developer argues that "morning larks, night owls and even those who work night shifts" all have very different sleep cycles, and the program should be flexible enough to cater for them all.
SunsetScreen is lacking in quick control options. It has a system tray icon, but there’s no rich right-click menu to configure its functions: you can only close the program or show its main window.
That’s perhaps to be expected for a first release, though, and if you need its extra configurability then SunsetScreen is still worth a try. We’ll be interested to see how it develops.