All of the visually appealing artsy stuff I've seen, involve LEDs. I think the cube is a great idea.
I'd Google LED Projects, and see what else is out there that you might be interested in for decoration in your technical room.
The scrolling message LED display is something that you can change text on when you feel like it for fun.
There are other interactive LED projects out there that might catch your fancy, or just plain old sequential or random LED pattern generation.
Good luck putting something appealing together that you're happy with.