I wanted to learn a bit more about electronics (at least at a high level) and decied to put together a computer around the Motorola 68000 processor, that powered more than a few classic machines, including the Atari ST and Sega Megadrive.
Limbo? Again, not dead. It's still sat on my desk as a bunch of breadboards, ICs and jumper wires. It was successfully running a program from ROM that I burned using an Arduino shield I designed. The only output was via an 8 channel logic analyser, which isn't ideal when you're dealing with a 16bit data bus and even wider address bus. When it came to adding a DUART for serial output, things seemed to get unstable and I struggled to work out what was wrong with the limited debugging facilities I had available. I've started several PCB designs for some kind of backplane based system, but failed to take it further. I've recently purchasesd a 16 channel logic analyser, so perhaps it'll be running once more sometime soon.