in the past i have used cloud9 and nitrous.io for teaching, and i had students clone a template repo with exercises and lessons. this is awesome to me because its a much more structured way to manage projects, especially for students who haven't used git before.
one tool which i have built with my co-teachers in the past is a problem generator that tracks which concepts the user has "mastered" based on the number of problems they have solved for a given concept. we had a naive problem generator that used templated problem specs with randomly generated values: https://github.com/pftp/pftp-web/blob/master/practice/python...
have you considered anything of the sort for students who want more practice?
