>>Gregorian chants<<
Don't laugh - Simon Cowell produced a group called "Il Divo" - operatic singers, singing contemporary tunes. KSFO's morning show played them singing Toni Braxton's "Unbreak my Heart." You know, it wasn't bad, but I'm over 45. :-)
I saw a TV commercial today for that CD. They opened the commercial with "Produced by Simon Cowell" or something similar.
They sounded pretty good to me too.