Here’s a video demo:
As Arith-Matic, Richard has been selling modules for teaching the rudiments of low-level computing - and now that’s built up into a computer. It does use an Arduino as a convenient program loader but that seems to me like a good tradeoff. It runs at 40Hz, presumably all the better to teach you with. It’s not quite open source yet, but will be. The next step is to write more software for it.
(via Ken/monsonite’s post over on anycpu)