How I Use It
This is great to use as a refresher for the students, or another way to present the material, not so much as a "fun" way to learn new material. If the students need to figure out how to work a problem but the teacher is unavailable for questions at that time, Khan Academy can be used.
As supplemental material, it is great. Or it could work for a student who has been absent but doesn't want to miss the material. Not really sure how it could be implemented as a whole class activity, but terrific for individual use!