lptMon website
As far as I can tell this is the first project I published in any sense. It used the parallel port to drive 8 LEDs and read one button. The four green LEDs showed CPU usage (25-50-75-100%), the left two LEDs alternated when there was a new email in KMail, and the right two LEDs alternated when there was a new RSS item in aKregator. Good old KDE. The push button cleared the alert state.
I used to occasionally swap the green LEDs around to stop from wearing out the 25% one too much.
The web page (linked above) is original.