Recently I was reading The Seven Day Weekend by Ricardo Semler on my day off. There's a chapter or so devoted to the Lumiar School he founded, which runs on a Mosaic curriculum—a curriculum which discards the traditional subject orientation for learning experiences. Here's an article written about it shortly after the school opened: Learn what you want.
What we need to change to go along with this (if we keep them) are the standardized tests (by subject). I think there need to be many questions offered, from which the student can choose, and the final score needs to be more like tower diving, where your score on what you attempt is presented alongside with the average difficulty rating. Brownose U. could prefer to admit students with a 100% score at the high-school senior difficulty level, while Speed College could prefer to admit students with an 80% score at the level of a third-year undergraduate (in their chosen major)—tailoring their environment appropriately. Survival of the fittest lacks vitality unless there's real diversity in the methods employed.
Once upon a time, the problem with taking this approach is that having some of your brightest students going deep into difficult sub-topics (such as a bright high school math student who takes a shine to number theory), was that too many students would get too far ahead of the teachers, because few high school math teachers (for example) would be able to ace the entire panoply of twenty offered questions.
With the technology of social networking, it's a solvable problem to hook bright students up with teachers with expertise in the subject area, no matter how deep and narrow. If there are ten high-school math prodigies in all of Brazil who take a shine to number theory, you just need one math teacher (available online) who is good at number theory to help shepherd their studies in a productive direction.
No matter what the child wants to learn, find the teacher who can teach it. In a system as large as Brazil (to continue with my Lumiar example) it can't be that hard to have a least one teacher who can keep up with a bright child no matter how unusual the learning passion (excepting all things Narnia, like astrology and phrenology and intelligent design).
We have far less excuse to funnel every child down the same subject-matter cattle chute than ever before.