I have taken few free online courses on these sites and I find them very useful in my development of Computer Science knowledge and web development skills.
If you are a passionate software developer like me, you would find a bunch of courses that interest you. Then, your real issue is to juggle the time slots in your schedule to fit in all of them. Sounds like a discrete optimization problem to me (still thinking in terms of Computer Science).
Coursera
https://www.coursera.org/
10gen Education
https://education.10gen.com/courses
Udacity
https://www.udacity.com/courses