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.
People who came by my booth at Maker Faire were able to tweet about my project. When they did, their tweets were displayed on the Apple ][ live and I generated a mosaic of all the folks who did so.
You can see below the LORES and HIRES versions of their Twitter profile pictures:
See it running on YouTube