Matt Mets’s Thing-a-Day projects are getting ridiculous:

Tonight’s project is a physical flag that attaches to my computer and goes up when I have new mail. First, I found biff, which is an extension to Thunderbird that proves a socket interface to poll for new mail status. Then, I wrote a little Python application to continuously poll the status and update the flag as necessary. Since I already had one written and didn’t feel like looking into any libraries, I used a C program to turn pins on the parallel port on and off to trigger the hardware. In a final bit of ridiculousness, I actually used some 555 timers to make an H-bridge to control the motor (don’t try that at home).

He released all the code and schematics. – Link.