In 1991 I dinosaur'd together a bunch of discarded 8086 and 8088 parts to make a free working 8088... my first complete computer "assembly". I had been working on computers - both Mac and PC - prior to that... but that was my first true assembly from the "bottom up" and without any instructions or interwebz to guide me.
Not that impressive I realize - but it certainly makes me feel old.
Not that impressive I realize - but it certainly makes me feel old.