My experiences (Score 1)

As a father of a pair of very bright boys (now ages 12 and 16), I have struggled constantly with this, We have tried several different schools and systems and have learned a lot along the way. I have learned that the "secret" to maximizing interest and learning is to keep the students continually engaged with ever more challenging activities. If you think about a traditional school environment, you realize that with systems having many students working at the same pace, you are guaranteed to have many of the students at least partially un-challenged. Also, with traditional environments, a forced schedule guarantees that either you have significant empty time between activities or that you are often interrupting activities. For very young children (ages 3-6+), we have found that the Montessori system of teaching does a great job of continually challenging students due to the individualized approach. Also, some computer based tools do an excellent job of challenging students at a pace tailored to their specific needs. After the Montessori years, we have founds the best approach is a home-schooled environment supported by some of the excellent available online curriculum and/or outside coaches (i.e. music, language, sports or specific focus areas). In the early high school years we have achieved excellent results by simply adding college classes to the program.