Hi there

use ULN2003 for managing large current and make diplay bright enough.
define reasonable number of registers in RAM to twist the data the way it is to be shown.

and your message board should be able to show text in multicolor, use tri-color LEDs. It should either scroll upward or donwward. It should run either from left or from right. It should be able to start message in the middle and send left half to left and right half to right.

It should have fill-board effect means send a word to the end and then send next word.

It ...... should force the viewer to go dizzy, faint and fall.

Simon