In the 1980s we downloaded games from the radio

Something I also remember from tv was what I think they called data bursts, at the end of certain TV shows they would play a few seconds of still frames full of information, like flicking through a magazine in 10 seconds. You would record this on a VCR and play it back frame by frame, occasionally it included some computer code to manually type in, it was pretty terrible because paused video frames tended to be a bit unstable.

Datablast, and Tom Scott has a video on it: https://www.youtube.com/watch?v=VBs_ABt-hRc

It's one of those ideas that makes a whole lot more sense at the broadcast studio where everyone edits on consoles[0] tied to Betacam decks that have exact, to-the-field seek timecodes and stable freeze frame capability. Even a 4-head VCR would utterly ruin it though.

[0] https://www.youtube.com/watch?v=AEMdmnNbCZA