The code.jsoftware.com wiki (which is a mediawiki site) might wind up using github pages for some of its more "code-oriented" content.
While mediawiki offers a great set of presentation tools, github wikis provide better integration with developer workflows.
Also, we're working on putting together a webassembly implementation of J, and github provides the right kind of infrastructure for maintaining that kind of system.
Anyways.. for now, I am using rdm.github.io as a scratchpad for demonstrating some of the deployment-related concepts for this project for others on the team. (The link in this paragraph includes an html file which references an image file and a javascript file.)
You can see this site's files in the matching github repository.