I used a fake antique (replica) that I picked up for cheap on ebay. I took out the clock work, and replaced it with a servo and used a phidgets USB - servo controller so I could control the servo from my computer. I had to use some gears so that the needle shaft would turn 360 degrees, since the servo only turns about 180. I also re-designed the face of the clock keeping a similar look to the original time piece. Once that was all set I created a little flash application that would connect to yahoo! weather service, and update the servo. I made it so it could toggle between current condition and the local forecast, and also made it so I could enter another zip code to see what the weather is in other places.
Gotta love those API hacks that involved hardware.
My only question is... Where can I buy one?!