Had one. 1982. Still remember sitting in a large swivel chair in front of a huge TV late at night when no one needed the TV. Boosted the beast to 16k of RAM but was always frustrated trying to save and recover my programs on the cassette tape. ("You kids have it easy!" he said from his rocking chair on the front porch.)

My dad was one of the first people to use computers in human resources for a shipping company, Matchbox, and then PBS. He brought the ZX81 home and I had no real idea what it was.