Just curious, but any chance of Khan Academy adding Discrete Mathematics? Correct me if I am wrong but I don't think coursera/udemy have a course either. The only free online course I am aware of for Discrete Mathematics is MIT OCW 6.042J.
It is a pity though. It would have been great to see KA covering Theoretical CS as well as Discrete Math.
http://ocw.mit.edu/courses/electrical-engineering-and-comput...