Feels like magic

The screensaver logo in full screen, with a counter for how many times it has hit the corner while you waited.

Code-breaking tools and a cipher identifier for when you have a string of nonsense and no idea what it is.

Plain, well-sorted illusion collection with the explanation directly underneath each one, from café walls to impossible triangles.

A search engine built on its own independent index with no profiling of searchers, and filters that let anyone re-rank results by their own rules.

A German board game world that has hosted Carcassonne and Puerto Rico since 2001, complete with a slightly baffling lobby.

Brown bears standing in an Alaskan waterfall catching salmon in mid-air, live from Katmai, and the reason Fat Bear Week exists.

Plays the notification sounds of Slack, email and Teams on a loop so it sounds like somebody urgently needs you.

Two near-identical interfaces, one of them subtly wrong. Getting past the third level takes an unreasonable amount of care.

Opens as ASCII candy counting up on a blank page and quietly becomes a full role-playing game with a sea, a shop and a dragon.

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

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

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.

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

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.

Paint over the tourist, the bin or the power line and it fills in whatever should have been behind them.

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

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

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

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

A browser playground for HTML, CSS and JavaScript, plus an endless stream of other people's demos to open, read and remix.

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

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

Records a page as you browse it, capturing the parts a crawler cannot — logged-in views, video, anything behind a click.

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

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.

Click the cookie, buy grandmas, buy portals, accidentally summon something. The game that turned incrementals into a genre.

Recipes laid out as a table of operations instead of prose, so you can see at a glance what combines with what and when.

Hit the space bar for a five-colour palette, lock the ones you like, hit it again. The whole tool is that loop.

A few hundred browser escape rooms in one filtered shelf, all running in the tab with nothing to install and nothing to buy.

Scores films for you by finding users whose past ratings track yours, then weighting their opinions. Recommendation with the maths shown.

Translates a cron expression into plain English as you type it, then tells you when it will next fire. Ends a very specific argument.

Wordle in reverse: you are handed the green and yellow clues and have to reconstruct the guesses that could have produced them.

An explorable on how ideas and riots spread through a social network, with the contagion thresholds under your control.

Chain encoders and classical ciphers together and watch text transform between formats at each step.

Builds a gradient visually and hands over the CSS, including the awkward multi-stop and radial cases.

Recreate a target image in as few characters of CSS as possible, then watch somebody do it in half as many.

Tower defence from the villain's side, defending your gems from heroes using demons, orcs and the undead.

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

A hundred consecutive interface prompts delivered by email — the sign-up flow, the 404 page, the calculator, day by day.

Fly a helicopter, wall off territory with towers, then defend the shape you just drew from everybody else.

German satirical news delivered with a completely straight face, plus a weekly video bulletin, running since 2008.

The 2007 original that turned maze building into a genre, played across a desktop with the icons still sitting on it.

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

An avatar library where you can dial through a dozen illustration styles and copy the result straight out as an image.