Actually learn something

GCHQ's public knife for decoding and decrypting data, built by dragging operations into a pipeline.

Long, carefully researched articles on forgotten disasters, obsessives and near misses from history.

Screenshots of manipulative interfaces caught in the wild, named and dissected. Grimly entertaining reading.

A weekly newsletter of unusual public datasets, with an archive of thousands you had no idea were collected.

Over a hundred thousand high-resolution scanned maps, georeferenced and free to zoom into more or less indefinitely.

Several hundred cipher, code and puzzle solvers in one place, from Caesar shifts to crossword pattern matching.

Harry Brignull's catalogue of interfaces built to trick people, complete with a hall of shame and the resulting case law.

A weekly newsletter of thoughtful links on design, technology and cities, with every past issue readable on the site without signing up.

A graphing calculator good enough that people make art with it — type a function and drag its parameters about.

Photographs of the city's abandoned schools and factories, paired with the records of the people who taught and worked in them.

Alarming research site about a chemical found in tumours, acid rain and every reservoir on earth. The chemical is water.

The original single-player dice conquest game: no accounts, no sound, no explanation, and still a perfect twenty minutes.

A tank shooting polygons for experience, then branching down a surprisingly deep upgrade tree, from the maker of Agar.io.

One search across thousands of American libraries, archives and museums, with curated exhibitions layered on top.

A browsable index of every named dinosaur, with size comparisons and the period each one actually belonged to.

The catalogue of every physical release ever pressed, down to matrix numbers and pressing variants, plus what your copy is worth.

Ankh-Morpork rendered as a text world, with guilds, working shops and an obsessive attention to what Pratchett actually wrote.

Machine learning journal where every paper is an interactive diagram; publication has stopped, the back catalogue has not aged.

Serious dithering workbench with dozens of algorithms, custom palettes, live preview and a video mode as well.

The deck-building game that invented the genre, officially online, with a free rotating selection of kingdom cards.

Precise Hindu calendar giving tithi, nakshatra and auspicious timings for any date and location. Astronomically rigorous throughout.

Yu-Gi-Oh played manually against real opponents, with every card ever printed and no automation to hide your mistakes.

Thirty-two Wordle boards at once, thirty-seven guesses, no mercy. The logical end point of the whole 2022 craze.

JavaScript demos in 140 characters. The gap between how little code there is and what appears is the whole appeal.

A rotating globe with every wind current on Earth drawn as moving lines, and layers underneath for ocean currents, particulates and the jet stream.

The carbon intensity of the grid across most of the world, coloured by how clean each country's electricity happens to be at this minute.

Every emoji with its meaning, its history and how it renders on each platform. Settles arguments in one link.

The professional encyclopedia, still going, and a useful second opinion whenever Wikipedia gets contested.

A scatterplot of six thousand music genres you have never heard of, each one clickable for a sample and a list of its bands.

All 2^122 version-four UUIDs listed in order with a working search box, on a page that should not be able to exist.

Writing community from 1999 where each subject gets personal essays instead of an encyclopaedia entry, and the tone never settles.

Design a creature from joints and muscles, then watch a genetic algorithm spend hundreds of generations teaching it to limp.

Idle evolution from primordial soup to interstellar empire, with dozens of species branches and an enormous technology tree.

Philosophers dropped into absurd situations, with an explanatory footnote in case you skipped that seminar.

Hundreds of playful projects from Google and creative coders: AI drawing games, music toys and odd interfaces, most of them running in the browser.

Paste a terrifying shell command and it pulls the whole thing apart, annotating every flag from the relevant man page.

The hub for playable posts — effectively the index for the entire genre of learn-by-fiddling essays.

An idle game built on actual differential equations, with optional theory levels that teach you the mathematics as you climb.

NASA's real-time 3D model of every mission in flight, letting you ride along with a probe on its actual trajectory.

Short, sourced facts arranged so one leads into the next. Built for the specific pleasure of learning something you can repeat.

London has been dragged underground by bats, and the writing is far better than that sentence suggests. Free, endless, faintly sinister.

Build a circuit and watch current move through it as coloured dots, with an oscilloscope available on any node.

The official fantasy football game: free, enormous, and the reason several million people care deeply about a Wolves fixture.

US government training films liberated from federal vaults. Sincere, badly acted, and occasionally about surviving a nuclear attack.

Home of the format that turns text into large letters made of smaller letters, with the whole font archive attached.

A fortnightly digest of measurable global progress on disease, energy and conservation, with a source for every claim.

A flag revealed six squares at a time, which sounds straightforward until you meet the fourth consecutive tricolour.

Flight tracking with the operational detail attached: delays, diversions, taxi times and the filed route rather than a tidy curve.