Khan Academy

http://www.khanacademy.org/

Imagine if all schools would use this model for math education: http://www.ted.com/talks/salman_khan_let_s_use_video_to_reinvent_education.html

There are studies that indicate that if children study in groups of four rather by themselves, the knowledge can be retain at a much higher level. In one study, 76% pass rate was recorded directly after the class and 76% again 6 months later.