My wife and I have taught our daughter materials sometimes 2 grade levels above where she is. I think every child has the potential for genius. It is really how you present the material.

I taught a few classes last year on how to program in Scratch to grades 1-5. The 4th and 5th graders really loved it and they went off on their own to learn more. It was not a large sample, but I think presenting the right material in the right way to the right age makes a huge difference.

I have been thinking of ways to improve education. I think there is a huge potential in online video. If it is produced right in the sense of say "Hollywood" verse say Khan Academy, kids will enjoy it a lot more.