Projects

10K en la Sierra is a directory of every 10K run in the mountains around Madrid: the Sierra de Guadarrama, the Cuenca Alta del Manzanares, the Sierra Norte and the Sierra Oeste. Road, trail and mixed races from 9 to 11.5 km, in Spanish and in English.

All the races are on one map with 3D terrain, topographic and satellite views and the Cercanías train lines. Each race has its own page with photos, whether registration is open, how many spots are left, and the full route with its elevation profile. There are pages for each region, for road or trail, and for the Christmas races.

You can make a free account to save races and get an email when registration opens, or sign up for the monthly newsletter.

There's no admin screen. A Claude session keeps the data fresh every day through an admin MCP server, signed in with OAuth 2.1. The site runs on Rails 8.1 and Ruby 3.4 with SQLite, Inertia.js, React 19 and Tailwind 4, deployed with Kamal on Hetzner.

e4e5Nf3 turns the chessboard's coordinates into quick games. You name squares, find them, call their colour, spot mates and drill your openings, until you know every square by name.

There's one rule: you never click or drag a piece. Every move is typed the way it's written on a scoresheet, like Nf3, Qxf7# or 0-0. Never learned how? The first game teaches you.

You can play as a guest, or sign in with just your email to earn XP, keep a daily streak and build a map of which squares you know cold and which still need work.