Actually learn something

City building from the Stone Age to the near future, with a tactical battle grid and guilds fighting over a shared continent.

Street-level archaeology of the city — old lamp posts, painted signs and vanished railways, walked and documented since 1999.

The 1978 electronic memory toy rebuilt faithfully in a browser tab, still beating most grown adults somewhere around level twelve.

Competitive FreeCell with timed deals and a global ranking, which should not work as a concept and completely does.

Answer vocabulary questions and the ad revenue goes to the UN World Food Programme. Running since 2007 and still counting grains.

A million questions written and edited by volunteers since 1999, filed under categories nobody would ever think to commission.

A hosting hub for hundreds of amateur incremental games, sorted and playable in the page. Where the genre does its experiments.

The French national library's digital collection — manuscripts, maps, newspapers and photographs, millions of items deep.

Conway's cellular automaton with a library of known patterns, still the clearest demonstration that rules alone make worlds.

Seven levels of talking a language model into revealing a password it was told to protect. The best hands-on lesson in prompt injection going.

Hans Rosling's animated bubble chart of the world, still the fastest cure for being wrong about global development.

An interactive world atlas you can scrub year by year from 3000 BC, watching every border redraw itself.

Real-time fog-of-war conquest on a grid, one army tick every half second. Simple rules, brutal depth, matches under ten minutes.

Walks you through rebuilding classic algorithmic pieces — tiled lines, Joy Division, cubic disarray — one step at a time.

Geometry, algebra and calculus tools in one place, plus a huge shared library of constructions others have built.

A three-by-three grid of geographic categories where you name one country per cell and get scored on how obscure it was.

The game that made the genre: dropped into Street View, guess where on the globe you are. The free tier is thin these days.

A community-built geography quiz mixing street view, flags and country outlines, with private lobbies for a group of you.

Long-running newsletter and link hoard for glitch art — tools, artists and the occasional genuinely disquieting find.

Industrial fishing vessel tracks worldwide, rebuilt from satellite signals, showing exactly where the world's fleets have been working.

Satellite-derived tree cover loss for anywhere on Earth, week by week, with alerts you can zoom in on until you are looking at one hillside.

One mystery country a day, guessed by warmth — every wrong answer shades the globe a little closer to the right one.

The whole planet in 3D in a browser tab, with guided Voyager tours for when you would rather be told where to look than choose.

Plots how often a phrase appears across books printed since 1500. Watch a word arrive, peak, and quietly fall out of use.

Solitaire variants you have never heard of, with a hint button and an interface built by somebody who actually plays them.

Comic-strip teardowns of real product decisions, each one explaining the psychology behind why it did or did not work.

Free cryptic, quick and Everyman crosswords every day, plus the setter blogs that explain each diabolical clue afterwards.

Look at a scatter plot and guess its correlation coefficient. A statistics lecture disguised as a slot machine, and it works.

A boarding-school story with robots, forest gods and a plot that has been quietly paying things off since 2005.

Daily coverage of hardware projects that had no commercial reason to exist. Reliably the most inventive corner of the web.

Grey text on beige, no images, and the best comment threads anywhere about how technical things actually work. Search covers twenty years.

One word of reassurance about the Large Hadron Collider, maintained since 2008 and still, reassuringly, saying no.

Seventeen million scanned volumes from research libraries, with full-text search running across the entire lot.

Football management one week at a time since 1997, with a transfer market and an economy run entirely by other managers.

Tells you exactly when the space station will pass over your garden, and which direction to look.

Every event on Wikipedia plotted as a dot across fourteen billion years, filterable down to one category at a time.

Tens of thousands of hosted model demos, each running in a browser tab. The closest thing machine learning has to an arcade.

Reaction time, sequence memory, the chimp test and verbal memory, each scored against millions of other people's attempts.

Charts and datasets tracking long-run trends in health, income and violence, useful ammunition for pessimistic dinner parties.

Spot the serif among the sans-serifs before the timer runs out. Ten seconds long and disproportionately stressful.

Every known way to lace and tie a shoe, diagrammed by one Australian for over two decades, including a knot he invented himself.

Several hundred psychological tests, from serious personality inventories to deeply unserious ones, all free and all instant.

Overlays one country on another to scale, then works out how your life expectancy, income and odds of various things would change there.

A map of the solar system drawn to true scale, meaning most of your scrolling is spent crossing absolutely nothing.

Catalogue, reviews and play links for four decades of interactive fiction, maintained by people who take the form extremely seriously.

Free illustrated repair manuals for phones, laptops, cars and appliances, plus teardowns that name and shame every glued-in battery.

Popular science headlines with the volume turned up, handy for the fact you half-remember reading somewhere.

A philosophy department's catalogue of illusions, each with what it is, what it demonstrates, and the argument still going about it.