[jitter] big display 8bits "interface", controlled by jitter

hello
maybe this itŽs a common threat, although my search wasnŽt successfull i finally ask

when you want to build a display made of whatever you want (bulbs,leds,flowers) in grayscale 8bits 320x240 and control this with a computer (max), what interface can someone use, 
an interface of 5120 8bits outs!!
uhm.. thatŽs hard, 
so i think what about amplify a display attached to the computer?

there is a lot of projects like this around, 
how they do it?