I was interested in making something when all these RGB LED Panels started appearing on adafruit et al. So with my girlfriends birthday coming up I thought it would be good to give a present that was a little different. Plus she had just discovered Adventure Time.
I drafted each of the enclosure pieces in CAD and constructed the housing using sheet acrylic and acrylic cement. I adapted the code from Jianan Li's blog who made a similar tetris matrix (see links for details). I can't recall how I converted the BMO bitmap I had drawn into a c byte array but it was using some software program (It's been a year since I finished this).
I had experimented with a few diffusers for the RGB Panel and found that photo paper worked quite well.
All for the Matrix was done in accordance with SmartMatrix Library and the buttons were mapped to any leftover IO pins (see the Git repo for specifics).
Yes the wiring is a birdnest as I was on the clock to get this done before the looming birthday.