Is there anyone who doesn’t know about Khan Academy, the free online school? A favorite of the digiterati, this website was founded by Sal Khan who started out by making video tutorials on how to learn algebra. He captured his instructional doodles on a black screen (rather than focus on his talking face) and these short intense classes were amazingly effective. Our son used them for high-school math summer school. Students love them because they can go their own pace, and back up when needed. Sal Khan branched out to cover almost every other school topic, from history to economics, in over 4,000 videos. I’ve searched for, and attended, specific lessons in his Chemistry set in order to brush up on a forgotten point. While his math and SAT prep ones are still the best, all his courses are free, and he still teaches better than the average teacher.