While I'm assembling the computer for the space, I've also been thinking about our desire to have some kind of indicator when something happens in IRC and I think I have just the thing.
I plan to put a piece of plexi in the front cover of the case behind the wire mesh. It will have a wooden frame (painted black and mostly invisible) that will contain a bunch of RGB LEDs. These will be pointing into the edge of the plexi. The TechWorks logo will be engraved in the plexi. When the lights are on, they shouldn't illuminate the clean plexi much, but will definitely glow when they hit the engraved logo.
The LEDs will all be connected to an AVR, which will be connected to the onboard USB headers. We can control the brightness of each color on each LED independently just by sending commands at it over USB (likely using a virtual COM port for simplicity). Imagine having it glow a cool blue while idling, only to flash orange when a message comes up on IRC. Or having colors run around the edge of the frame. Or having it slowly morph between purples, greens, blues, etc. Colored LEDs are fun. The light could vary with time of day, system load, various events in IRC, or just about anything else we can think of.
This is the case that I bought. You can see the mesh grill all along the front. I plan to put this plexi emblem near the bottom, where you might otherwise mount a fan. There are 120mm and 140mm mounting holes here, so I will try to make it mount on the 140mm holes.
The LEDs I have are 5mm RGB with common cathode. I plan to use 3 on each side for a total of 12. To control the brightness, each side of 3 will have an NXP PCA9634 8-bit PWM LED driver with I2C bus. Each side will have a long, thin PCB with the LEDs and LED driver mounted directly on it. The power and bus will go from the controller to the plexi frame with just a few wires and will daisy-chain from between the PCBs around the frame.
Any other ideas? The AVR should have a very light load, so it could also do other things. For example, I have a piezo vibration sensor, some temperature sensors, and even some CdS cells. I could also get a microphone and hook it up.