BrainTurk

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

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

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

Millions of chess tactics pulled from real games and served at exactly your rating, entirely free and with no account required.

Where the bridge world actually plays: free tables at every hour, tournaments, and teaching rooms of remarkable patience.

One page per leak channel — WebGL, canvas, WebRTC, DNS — each showing precisely what your browser hands over without being asked.

The Second World War version of the same slow, sprawling map game, with research trees and alliances that rarely survive contact.

Type any web feature and see which browsers support it, version by version, alongside how many people actually use each one.