Coursera is one of the popular online course and is currently conducting free course for Crypto Currency geeks and the course has been already more than 1 million enrolls.
How about you? Would you like to enroll also with the same course?
I am actually enrolled there already. It is a 11-week course training about Bitcoin. Most of the lecturers were from Princeton University. I am on my 2nd week and I must say that I enjoyed gaining knowledge in Coursera. Since Bitcoin is becoming a huge thing globally, it's good that we learn about it and not just go with the flow. If you haven't enrolled yet, I suggest that you do it ASAP. The course though does not offer a certificate but anyway it's free and the knowledge are worth it.