No sign-up, no email

A free endpoint that returns one cat fact per request, which is how every cat-facts prank bot ever built gets built.

Twenty years of forensic argument about how tall film stars really are, with photographic evidence and footwear analysis.

Estimated fortunes for anybody famous, sourced loosely, and impossible to stop clicking once you look up the first one.

The four-day jam game that grew into Celeste: thirty screens of very precise dashing, running in the page at PICO-8 resolution.

Anime avatar makers with genuinely good line art, including versions that output something usable as a profile picture.

Per-component checklists — buttons, forms, cards, empty states — covering the things everyone forgets until review.

A stocked chemistry bench in the browser where you can mix reagents and get it badly wrong at no cost.

Chess tactics training with a rating that goes down, plus an endgame trainer that reveals exactly how much you do not know.

Nearly a million recorded games from four centuries of chess, replayable move by move, with the real arguments in the comments.

A chihuahua rotating to a dance track, which was apparently a complete website idea in 2013 and somehow still is.

Long branching novels where your stats matter and the prose does not embarrass itself; a good number play free in the browser.

Community-written choose-your-path stories with ratings, which is the only thing keeping the good ones above the fan fiction.

Google's stripped-back sketchpad — pencil, pen, marker, chalk — with pressure support and absolutely no other features.

The offline dinosaur from Chrome's error page, playable while you still have a perfectly good connection.

Fourteen small experiments — spectrogram, harmonics, arpeggios — that explain how music works by letting you break it.

A history map with a timeline slider, layered with rulers, religions, battles and linked encyclopedia articles.

Scanned American newspapers from 1770 to 1963, full-text searchable, which is a dangerous thing to discover on a weeknight.

Five photographs, one question each: what year was this taken? Points scale with how close you land, and the cars always give it away.

How far you can get by train from any European station in five hours, drawn as coloured bands. Ruinous for an afternoon's productivity.

Parody religion with its own prophet, apocalypse date and merchandise, committed to the bit long enough that you stop being sure.

Open-city driving with traffic and no mission attached, for when you want to obey a speed limit in peace.

Video walks through a real city, and your job is to work out which one from the shopfronts, number plates and pedestrians.

Renders every road in any city as white lines on black and nothing else, which turns an ordinary street plan into unexpectedly good art.

Decades of adverts preserved exactly as broadcast, including the jingles you will regret having remembered.

Several thousand DOS, Amiga and console titles catalogued with screenshots, each playable without leaving the page.

Paint over whatever is ruining a photo and it fills the gap convincingly. Free at standard resolution with no account.

Click monsters, hire heroes to click for you, then ascend for souls. The clicker that dragged the whole genre onto Steam.

Viral-content parody taken well past the point of sense, including quizzes that insult you for finishing them.

Sixty seconds to forge the Mona Lisa with a mouse, then a pixel-by-pixel score telling you exactly how badly it went.

A global membership devoted to looking up, with a cloud of the day and a manifesto against blue-sky thinking.

Curated stumble button that sends you somewhere good rather than somewhere random, with categories if you are feeling fussy.

Mash any keys and immaculate code appears on screen at speed. Enormously convincing to anyone standing more than a metre away.

The word-association board game in a free, well-built online room: two spymasters, one grid of code names, nothing to install.

Run a coffee stand for fourteen days, adjusting recipe and price daily, and learn more about margins than from any lecture.

The murmur of a café without the queue or the cost, built on research that moderate background noise helps creative work.

A plain, ad-free bank of cognitive tests — n-back, digit span, Stroop, mental rotation — that keeps a history of your scores.

Settlers of Catan in a browser tab, complete with the trade negotiations and the one player who will not give you wheat.

Match hue, saturation and complementary colours against a target, one exercise at a time, scored out of a hundred.

Hand-picked four-colour palettes posted daily and sorted by mood, with none of a generator's randomness.

Palette generator trained on photographs and films, so the colours it suggests look like they came from somewhere real.

Team deathmatch with a built-in level editor, played mostly by people who memorised every map years ago.

Petabytes of crawled web pages released free for anyone to analyse. Most of the language models you have used started here.

Interactive models of what complexity science likes best — epidemics, flocking, synchronisation, forest fires.

Sixteen words, four hidden groups, four mistakes allowed. The traps are the entire point and they are very carefully set.

An audio museum of sounds made by objects that no longer exist — dial tones, shutter clicks, the whirr of a rewinding tape.

Home consoles from the Atari era onward, running in the browser. Mostly worse than you remember, which is part of the appeal.

Guess the secret word and be told only how semantically close you got. Rank 4,000 feels like progress, and it very much is not.

Home of Conway's Game of Life — pattern archive, wiki and a board for setting your own cells running.