I've been putting some work into https://confwall.com - which has been running at ffconf for 7 years now and I turned into a product at the start of last year.
It's made the money back from the development investment (which is nice) and I need to find time to market it to business.
I'm also intending to put out training videos, based around the workshops I do in person. I've got 3 topics in mind: CLI for beginners - to which there's a short book being published by A Book Apart in coming months, Node: full development workflow (from coding, full test coverage and deploying), and Debugging in the client.
I just need to find time...!