CircleClock is a screenlet that shows a circle-shaped clock.
It's a simple digital clock. You can change the colors for front/back of ring and font from the properties. And, with v0.4 or later, able to turn on/off displaying rings for hours/seconds from the additional tab on the properties.
Screenlets is the name of both a set of independently-developed widget applications and the widget engine which runs them. The engine runs primarily on X11-based compositing window managers, most notably the Compiz (under Linux) architecture.