Mrs. BD and I listen to Teaching Company cds in the car. Well, it's called "Great Courses" now.
Best college course I ever sat in on is Bob Greenberg's How to Listen to and Understand Great Music. It's on sale now. I cannot express how absorbing and wonderful he is to listen to. It's life-changing, even for somebody musically-disabled like me.
Handel wrote Messiah - 50 gem-like and unforgettable tunes - in 24 days.