I think the Khan academy has a solution to this particular problem. Salman in his TED talk proposed that students view the videos in their own time for the basics, then engage in problem solving in class so that the teacher can devote much more attention to each student.
Experience with this shows that the kids simply don't watch the videos. It sounds brilliant - let the kids watch videos together, they can eat pizza, drink cola, laugh, text, watch the video again to get the bits they missed, and then come to class to work the problems and get help.
The experiment has been done - the vast majority of the kids don't watch the videos.
I'm pretty sure I read of it on a web site lunk to from here, but I don't have a record of it. I have seen it reported from at least two different people who tried it, but don't have a record of where I read it. Sorry.
EDIT:
I've found one reference to a teacher who's trying it but has some kids who don't watch the videos:
