As far as I know, those communities are pretty much non-existant, or they do not reach much beyond their institutes to the larger campus. In my institute (Biology Institute, at the Federal University of Bahia, Brazil), there are no tech clubs or anything of the sort. I am trying to initiate a culture of coding and using github, but most biologists have a strong resistance to coding, and prefer using ready-made software for their analyses. I teached an introductory R class last semester, and used github to host the course materials, using the wiki feature of the repository, as I was not aware of the Classroom feature.
By far the Student Developer Pack, the private repositories are a must for graduate students.
I don’t know about the whole campus, but I am starting an organization repository for the Lab I work on. The trick is to get ecologists and zoologists to code, and to share their code. People here are still too protective of their code, and still don’t have an Open Source mentality. Last semester’s class was a huge progress, but insitutional support for coding classes at the Biology Institute is rather weak. I will help a fellow teacher this semester on a C++ modelling class, and intend to used Github Clasroom, it will be a nice experience