I had the honor of presenting Coolhand Labs as one of the notable Ruby startups of the year at this year's RubyConf. More on that later — but one thing has really stuck with me that I want to talk about: How much fun top engineers are having building with AI.

I went in expecting a sour mood. Coding agents have exploded this past year, and I figured a room full of engineering legends would be watching AI upstream their craft in realtime and cynical about it. Nope: Actually, top Rubyists are having the time of their lives.

Exhibit A: Matz. If you're not deep in the Ruby world — he's the guy who created the Ruby language back in the '90s. His whole keynote was, basically, him gleefully walking through failured experiments and wins using AI to build Spinel, a new and better Ruby interpreter. He's brewing his own AI harnesses, watching AI-driven contributions to the project explode (~100/day), running AI loops to auto-close the issues he doesn't need to touch himself. Just clearly having a blast being at the top of his craft and multiplying it as far as it'll go.

Then I reconnected with Tom Black, who was buzzing about resurrecting his old side project, Ruby2D. We spent an hour playing games he'd built purely in Ruby — a ten-year-old roadmap he pushed further in a single week by running it through Fable5.

So here's the question rattling around my head: if you're a senior or principal engineer at the top of your game, how are you using all this to finally build the things you never had time for?

What are you making right now that actually brings you joy?