This year, Greach had a workshop day. Normally, I am not a big workshop guy. Attending a workshop sometimes means passing several interesting talks. However, Greach organizers did several things right. They isolated the workshops into its own day, and the workshop lineup was impressive.
I wanted to learn how to write Gradle Plugins for a long time, and @ysb33r's workshop was an incredible opportunity.
This link points to the workshop exercises; a fantastic step by step Asciidoctor documentation to learn about how to code Gradle plugins.