When I saw this project on Instructables, my jaw dropped. This project produces some amazing 3d looking effects with just a Rainbowduino and a 8X8 RGB LED matrix. The light is diffused with some tracing paper. This would be something cool to hang up in the office. It looks like the hardest part is getting the hole cut in the top of the box. I bet a laser cut hole would be nice. The author (giladaya) even provides some code and patterns to get started.
I really like the animation that kinda looks like a spinning galaxy.
The video is mesmerizing!
Check it out!