Just starting this thread to collect ideas for future workshops:
Coming up: At next CodeHub on 8 April we will do animations (with CSS, HTML Canvas, three.js)
We will have a Git and GitHub workshop in June, and a JavaScript workshop some time in the summer.
Have you seen the OpenTechSchool learning materials? You can find them at http://learn.opentechschool.org/ .
Yes, I have! And I have worked through some of them (set up http://codehuborg.github.io/ after working through ‘GitHub pages from scratch’). They are great, and I would quite like to use them for workshops. If somebody else organises (we’ll sometimes have speakers from outside the group), we will leave the format to them, but I will point them to the learning materials, too.
Seeing you’ve already had workshops on other topics in the past, is there any written-down curriculum for them we could reuse in the wider OTS community?
We have so far mostly had ‘mini-workshops’ within our group, and don’t have much written material. But for the last one on Node and Grunt we have material up on GitHub that could certainly be used for a workshop. https://github.com/CodeHubOrg/node-grunt-workshop
I’ve also put something on our GitHub pages about Unix File Permissions and Ownership. This is a classic example of learning through teaching, as I am in no way an expert, but instead benefited from researching it and creating this little workshop. Just hope I got it all right or did not miss anything obvious. That is the drawback when you are not totally familiar with the material and its context 
But I am definitely now much more confident with setting permissions!
There will also be material on GitHub for Animations (in fact some already… but we haven’t had the workshop yet)