Yesterday I listened to the podcast
Bits und so #135. There was
a little chapter about an really interesting application:
f.lux.
It changes the temperature of your screen colors to be like the naturally
light of the day or the night around you.
I tried it, and I find the colors really warm and they're not as bright as before. So I believe it will help me to work better in the hours of an evening or afternoon.
For all German readers: Golem published an article about f.lux, too.