From Trammell Hudson's Projects
I modified this random red/green LED scrolling sign to use a SparkCore as a brain. It now tells the time in UTC and .beats.
Since it is red and green, I call it the Christmas Clock. The alternate title is the anti-color-blind clock since I have the background turn on full bright. If you don't like it, you can build your own with the source code from github.
Like most of these displays it is a row-selected shift register. In this case there are separate red and green shift inputs, with a common clock and latch.
The original board was massively overpowered with an Altera FPGA for some reason.