I found Windows 7 HomeGroup failed when IPv6 was disabled. While this isn't a killer app, is pretty nice to have some domain-like sharing features available at home. So while it's not a killer app, I wouldn't counsel end users to disable it.

I believe you will get mileage out of using difference mediums. I recommend some short stories, a la Asimov's works (your choice). I also recommend some novels, such as the Ender's series by Orson Scott Card (plenty of social and moral questions in that, esp. the sequels).
I would also recommend comics. Superman and Batman are still known to the current generation through cartoons and movies, for the non-readers. You can look at the art as well as the topics and writing for different eras. There is a decent documentary by the History Channel, titled "Comic Book Superheroes Unmasked", covering comic book heroes from the 30's through the turn of the century.