I was excited to participate in the 2019 Astro Hack Week! Rumor has it that there were 300 applicatns for the 50 spots. It was an energizing week full of morning tutorials and lectures combined with afternoon hacking see here for a detailed schedule.
All the lectures and tutorials are available on the Hack Week github, I encourage you to check them out if you have even a little interest in data viz, querying surveys, bayesian inference, or machine learning.
My favorite serious toy is this site that lets you play with neural net nodes and activation functions. My favorite blowing-off-steam toy is the gihpy account we made to share our git puns and other gifs (upload still pending when I wrote this).