One of my favorite Mac OSX apps is Blacktree's Nocturne, which inverts the colors of the whole screen such that you end up with a black-on-white display systemwide that is easy on the eyes in a dark room. Example.
I went looking and it seems that there is currently no way of doing this for Windows. The closest you can get are either dark themes, which most apps will ignore (and don't solve the problem anyways - see my comment to Paul's answer below), or apps like F.lux or Friendeye that simply lower the brightness and/or alter color settings, but I found nothing that would actually invert the colors for the whole screen.
So my question is, is it even possible to write an application that would do this in Windows? Do DWM, NVIDIA drivers, or any other part of the graphics subsystem have any API that allow you to manipulate the rendered image at such a basic level? Where would one even being?
Question is more than a year old, but a more appropriate answer may be http://arcanesanctum.net/negativescreen/.
Works in windows 8 too, source code is in C#. It may solve straight away your problem, or you may read the source to expand functionality.
