Your Linux Self-Help Desk. A selection of mostly Linux related tutorials, howtos, fixes, news and more.
F.lux adjusts your display to the sun's color and brightness
And there's a Linux version with GUI add well, check it out: f.lux for Linux. This is great especially for people working on a computer and suffering from insomnia or e.g. if you have a work room without windows (glass filled frames that is).