The full catalog

Learn CSS selectors by writing them to grab the right plates, bento boxes and sushi off a restaurant table.

Grow a carrot patch by writing CSS Grid properties — a tiny, free game that teaches grid layout one level at a time.

Play the scheduler against threads of buggy code, forcing race conditions and deadlocks to learn how concurrency really breaks.

A sandbox MMORPG with no game client of its own — you play by writing code that calls its API to gather, craft and fight.

Build retro arcade games with blocks or JavaScript, then play them in the browser or on tiny handheld hardware.

A Scratch-like block language with a higher ceiling: custom blocks, lists, first-class procedures and serious CS ideas.

The modern Robocode: bots connect over WebSocket so you can write them in any language you like.

Two programs in Redcode fight for control of a virtual computer’s memory. The 1984 ancestor of every bot-battle game.

Write real Python to control robots, drones and machines in a physics-driven engineering sandbox.