I had a car radio that played MP3s from CDs. In the days before widespread cellular data, I used to download and burn hours worth of Librivox ebooks and older episodes of This American Life before long road trips.

It wasn't a great experience, because when you turned off the ignition it would only remember the track and not where you were within the track, so you'd have to do a lot of fast-forwarding when you came back to it.