YTClock

YTClock have two separate programs in the package, one is a very small core program, and another is a customization program.

Both are written in C++, and the core program directly calls the Windows API to make it very lightweight and to use the latest Windows capability. The clock is transparent both in terms of its inputs and outputs. To click the clock itself, you need to press the Ctrl key, or the mouse event will be delivered to the window underneath the clock.