I'm surprised this never occurred to me. K-12 education is mostly the same stuff every year, and it's not that sophisticated. You'd pretty much only have to compile it once. I'm surprised nobody in the free software or creative commons movements thought of it.
There's a huge interest in education material in the free software and creative commons movements. The idea of putting free education material on the web isn't new at all, and there's tons of material available out there (and has been for quite a while).
Khan Academy stands out because it's just really, really, really (really) good.
