Teaching
Alongside Sopha, I taught programming for ~1.5 years at Torne-se um Programador (closed community, project-based curriculum). Explaining things makes you understand them better — the cliché holds.
Open source
Two merged PRs into Rails: #53417 as author, and #47852 as co-author alongside Justin Searls, Aaron Patterson, and Guillermo Iguaran.
Beyond code
Started a bachelor's in Physics at UFMG this year — gravitation is my favorite part so far. The analytical habit shows up in code more than I expect: measuring before optimizing, modeling before guessing, treating systems as something to reason about rather than just patch.