Long before home computers were affordable, in a magazine for electronics hobbyists, I saw a design for an analogue circuit that could, it was claimed, remove advertising and DJ waffling from radio broadcasts. I think it just looked for the frequent short periods of silence that occur in speech so it can't have been very reliable. But it had a certain low-tech beauty.
I once had an ‘Intempo Rebel’ radio[1], about a decade ago, which had the selling point that it would record songs, from radio, as MP3, without any ads or DJs. It actually worked, from what I remember. It was magic to me at the time, and …still is.
Edit: it appears that its original name was PopCatcher [2], by a company with the same name
