My entry for RC 2017/04 will be a mingle-mangle of several things that are going through the back of my mind:
The Commodore PET 2001 turns 40 this year and I scored a defective one about a year ago on ebay. Some issues have been fixed already but the system is still disassembled and has to be tested as a whole. I assume the PET would appreciate to be reanimated at its birthday.
The Video Graphics Array (VGA) turns 30 this year. Having a weakness for graphic extensions (see my RC 2015/7 entry) my main entry to RC 2017/04 will be a PET/CBM Color Graphics Extension sending pixels to a VGA display.
The Atmel AVR 8 bit architecture turns 20 this year. So I’ll use this type of MCU for the graphics board.
Celebrating 40 years PET 2001 plus 30 years VGA plus 20 years AVR sum up to 90 years of Retrocomputing. That should comply with the RetroChallenge Rules quite easily.