Hoax- how eccentric do you need to be?

This weekend I watched the newly released DVD entitled Hoax, starring Richard Gere. I enjoyed it so much and I think it's one of the best movies that Gere has done in a while. If you're not familiar with the plot, it is based on the life of a man named Clifford Irving, who almost pulled off the bogus writing and publication of an autobiography of Howard Hughes. I mentioned it in passing to my 18 year old son and told him that it was very good and he might like to watch it. He asked me what it was about and when I told him it was about Howard Hughes, I was flabbergasted to learn that he had no idea who Howard Hughes was. I couldn't believe that my son who is pretty culturally savvy and an A+ student who regularly watches the History Channel would not know who Howard Hughes was. It made me wonder what other huge gaps there are in his cultural literacy and just how eccentric do you need to be to be remembered?