This was my first program, and I made it while learning C in 2002.
It was born with the discovery of a library called xosd for linux, and my desire to learn how to program "like a man".
This application overlays text information on screen, just like the OSD on tv's do. My program had a volume monitor, dial up connection (so long ago!) status monitor, XMMS plugin to show the song you are listening and a clock. All of them could be configured to display in different places around the screen, with different fonts and colors, and with the help of a Tcl/Tk frontend, you could write your own "themes" to load at login time and automate your preferences.
It was a simple concept, but it ended with a plugin architecture, multithreading and IPC implementations so it would work as a "daemon" or "background process" as it is known in other operative systems.
Anyway, it was nice, and to date I still get bug reports and some email traffic due to it has been included in the Debian ports. So, check it out, and try to convince me to go back to linux and fix it!!