I've been looking for a fun project to do, I was thinking of taking one of my older systems and adding some blinkenlights to a 3.5" or 5.25" front panel knock-out. Perhaps integrating it with a CF drive so that it would have additional functionality besides amusing me with blinking LEDs. My thought is you could probably easily route HDD and network activity to LEDs on a front panel, but how would you do processor activity LEDs?
This probably wouldn't be too important for a single cpu system, but I thought this might be fun to do with a modern quad core box and have a LED bar for each processor, and then have the percentage of activity show up as the number of bars that are lit. While I think you might somehow be able to pass the processor state to a parallel port, I'm not sure how you would do this on a modern system. Anyone have any ideas?