For the Winter Warmup Retrochallenge 2013 I plan to recreate the worst ever home console.
Dozy graphics design, Ridiculous Controllers, Terrible sound, this has it all.
This will involve (time dependent but at least the first three) :-
(1) Figuring out how it works. Because it is so bad this is relatively easy ; there's only one way it can actually be wired up. The games are so simple that you can rebuild them from screenshots.
(2) Writing an emulator for it (none exists)
(3) Rewriting the ROM and Built in Game (not dumped and may never be) working from the screenshots and manual descriptions available.
(4) Attempting to produce a hardware version on an Arduino (by my calculations, possible in real time with the Arduino generating the video because it is so slow and to make it worse the processor only runs in Vertical Blank) so anyone mad enough can play it on their TV.
(5) Trying to create a half decent game for it. This is by far the most difficult challenge.