My DH & I listen to Great Courses on long car rides and he especially enjoys them. We've done New Testament, Civil War, Peoples & Cultures. I think these are very adult/sophisticated. Big vocabulary, college-level thinking, references to things younger kids don't know yet regardless of intelligence. My kids may hear some, but I don't think they're kid-friendly for ease of learning. Now that my oldest is in HS, I bet he could do it, but I think I would first try the following, either on home computer or iPOD for travel:
1. Free downloads on iTunes U (as in university) for lectures from distinguished professors, stories, poetry, etc.
2.
www.cogito.org free downloads of interviews/talks--specifically designed for high ability kids
That way kids can pick and choose instead of committing to a full, many-hour course.
