Twitter display using an Apple II computer. Shown at Maker Faire Bay Area
Details on the build are at http://atomsandelectrons.com/blog/2010/04/apple-t/
Documentation is getting fleshed out. For the ambitious among you, take a look at Documentation.pdf which explains what you'll need to purchase to construct the PC->Apple II communication cable.
At this point there should be enough info and working code for a motivated individual to get their own Apple II Twitter Display up and running. It's mostly cleanup and better documentation that's lacking now.
See it running on YouTube