I attended the codebar workshop at Toucan Box in Hammersmith, London.
I acted as a coach, helping a beginner get to grasp with some web development fundamentals.
After a bit of mingling and food at the start of the event, the codebar work on depends on what the learner wants to do. They may be working through the codebar with something on their own project.
Being a coach, especially a coach for a beginner is a great experience. It forces you to really examine what you know and understand about a technology, examine how you learn and explore problems. More importantly it shows you how beginners learn and explore problems.
At the workshop I was helping a beginner get a better grasp of HTML and CSS for his job. Having to explain things like selector rules and how the rules are applied in specific situations forced me to confront some edge cases in my own (somewhat rusty) understanding.
If you are a learner or are interested in mentoring and coaching developers, I highly recommend you check out and get involved with codebar.