Of all the subjects covered within the Intelligence lecture, I was most fascinated with the coverage of the Abecedarian Project... sort of like a "Super Head Start" program, where they started with children from low-income families at infancy!
Now, the "Abecedarian Project" is a terrible name, if you know who the Anabaptist Abecedarians were (they tended to hate human knowledge so much, they wouldn't teach their children the alphabet). But that irony aside, this program is amazing, and exactly the kind of project about which I want to know. They gave these young children full time day care, as well as promoted language and social skills, and ensured benefits lasted into adulthood. I was also interested to read and hear that nutrition can play such a major role, as well as socio-economic status.
There is some talk among the other posts about the fact that White and Asian children score better than Black and Hispanic children. I don't think this has to do with anything other than socio-economic status and expectations of their parents. There is no "White" answer on an exam, versus an "Hispanic" answer.
If a child is told, day after day, that not much is expected of them, because their parents never made much of themselves, then they won't try. This isn't restricted to Black/Hispanic children, of course, but let's be realistic. There are more poor Black/Hispanic families(24.3%/20.6%, respectively) than non-Hispanic Whites or Asians(8.2%/10.3%), and it IS a cycle, based on the attitudes noted above. I imagine the poor families of all races score lower on the intelligence exams.

[source for poverty estimates: http://www.census.gov/hhes/www/poverty/poverty06/pov06hi.html]