I spent some time in a high school English class and had the pleasure of seeing LibriVox in action. I had never heard of it before today. We synced an iPad up to the Apple TV and listened to Chapter 24 of The Jungle by Upton Sinclair. While we listened to the story over the sound system, the tenth graders followed along in their books.
I'm not going to lie. The guy reading didn't exactly have the most entertaining voice, though he did try. He did some great hiccups and pretend drunken talk. I had never read the book myself, did not have a copy in front of me, and felt lost starting on Chapter 24, so I busied myself doing other things... including watching the students.
For the most part, I had zero relationship with any of the students in the room. We had joked and chatted a bit in the first part of class, and they did like to talk. It would have been easy for them to team up against the sub. However, when the audio started, they were focused on the book. Everyone was reading along (or at least appeared to be) and some of the students were even commenting aloud along the way. They were into the book as much I would hope that a group of teenagers would be into a book published in 1906.
After the chapter was over and there were only a few minutes left in class, they reverted back to their teenager ways. I got to hear how boring this class is and how they had no idea what was going on in the book.
But that half hour of listening to Chapter 24 was golden. They were reading and listening and engaging. Good stuff.
So, I have no idea what books are on LibriVox or if you can use it in your class, but it's worth passing along to you.