I was thinking of throwing in a game like Tetris with just accelerometer controls. That'll be after I find a job though. Numbers were actually the first things I displayed, I actually still have all the code to display them still sitting unused.

Text has been less of a success. Having the letters be easily legible takes more space than I would have thought, and the small pixel fonts don't look great with the big spacing between the LEDs. Maybe some scrolling text would look good, but I haven't focused on it too much. I tried getting a QR code displayed, but it didn't want to scan.

For buttons, I'm kind of married to the idea of no buttons. The accelerometer does recognize clicks and double clicks in different directions, so that might be useful for something.

I encourage anyone who wants to fork/contribute/post issues on this to do so and I'll try to be a good maintainer.