MC14500B Homebrew Trainer
This was the first "microcomputer" I ever built. My friend Don worked for a company that did industrial waste water treatment. He was teaching me about digital electronics, and found these parts. I requested some samples from Motorola, along with various support chips. I did as much of the design as I could, with Don helping me along. It was built on about 10 pieces of Radio Shack Breadboard. Unfortunately, this pre-dated digital cameras, so don't have any pictures of it.
Mine had a 20 key hex keypad for programming, 8 LEDs, 8 switches, 1K of program store, 32 bytes of RAM, and a 16 level call stack. I'd write simple problems to make the LEDs do different things based on the switches.
As I recall, I eventually disassembled it when I needed the plug-board for other projects. Of course, so many years later, I regret not having kept it, or at least documenting it.
See the MC14500B page for details about the processor.