A particularly simple way to do it might be to use Twine. Twine creates completely-client-side HTML+JavaScript pages. It's intended for interactive fiction, but I don't think that it'd be much of a stretch to use it for courses. Then the course construction could be done on github, and the github work could be automatically compiled into HTML+JS and dumped on courses.bitcointalk.org with some server-side integration added in.
It seems that there is an open-source EDX platform which could be used, but it seems really complex, and especially difficult for many people to create/modify a course collaboratively.
Yeah, I'd like to write some of the technical material, but I won't have time to oversee it properly. I also don't know much about the science of pedagogy. I'd be nice if someone with some teaching experience would volunteer to oversee the whole thing.
It seems that there is an open-source EDX platform which could be used, but it seems really complex, and especially difficult for many people to create/modify a course collaboratively.
I'm guessing your going to be the one overseeing this? Haven't you got got enough on your plate already? 
Yeah, I'd like to write some of the technical material, but I won't have time to oversee it properly. I also don't know much about the science of pedagogy. I'd be nice if someone with some teaching experience would volunteer to oversee the whole thing.