The author reports on a "flip model" of instruction that has gotten national media attention lately, thanks to its promotion by Khan Academy, the high-profile nonprofit online-tutoring library created by Salman A. Khan, a Massachusetts Institute of Technology graduate who was looking for a way to help his young relatives with their homework. The model--in which teachers introduce lectures online for students to access at home and then use class time for group practice and projects normally relegated to homework--is not unique to Khan Academy, however. The "flip model" of schooling calls for students to watch lectures online for homework and use class time for discussions, problem-solving, and labs. Critics, though, argue the model is too reliant on online materials and will prove difficult to use in schools without major technology infrastructure. Yet only recently has technology advanced enough to allow teachers to assign and track individual students using online material at home, and the flip model is still in the earliest stages of being formally studied.