Frank Zappa explains on one of his albums that he had met Johnny Cash earlier that day, and that Johnny would be playing a song with the band. Unfortunately, Johnny's wife got sick so he couldn't make it, but the band did play 'Ring Of Fire'.
You probably know the story better than I do.
All this as an intro to tell you that there's an album out that collects twenty different artists performing Ring Of Fire. Including Zappa's Best Band version.
Check it out:
-- info: Andreas Hosse