There are many screensavers that work as clocks, displaying time on your screen in a variety of ways whenever your PC is not being used. However, I must admit hadn't seen such an original clock before.
PolarClock shows the time in colorful concentric circles that are slowly closing as time goes by. The screensaver includes a complete configuration menu that enables you to choose language, luminance, size and other options. You can also select the hue range to use, although I would have preferred to be able to choose the exact color for each circle.
In all, PolarClock is a light, discreet screensaver that gives your PC a new utility as clock... at least when you're not using it.