Okay, okay! For all the none of you that care about the actual code, I've finally published it on Github:

https://github.com/JorjBauer/purposeless-led-display

... I don't particularly want to share the encryption key that I'm using for this because, well, that's my flavor of crazy. I've finally expunged it from the archive, which means starting anew from this point on.

There are four subdirectories in the repo.

Gateway

The gateway (a Moteino with RFM69HW) is the "sending" half of the radio pair. It's directly connected to my Mac laptop via whatever TTL-serial-to-USB dongle I have sitting around.

Receiver

The receiver (a Moteino with an RFM69H and onboard flash) is embedded in the LED display. It shuttles packets back and forth from wireless to the Pro Mini "driver" via TTL Serial. It is also the timekeeping source when the display is in "clock mode".

Driver

This Arduino Pro Mini is responsible for running the LEDs. It expects commands over serial, and spits out replies the same way. Its bootloader has been overwritten, which means it can't be programmed directly via serial any longer.

Supporting

There are a bunch of Perl scripts in here that I use to send commands out the gateway. Many are just stub pass-throughs to Display.pm, but a few (like "programProMini.pl") are a little more complex.