A brainstorm, not a spec. Everything here runs in the browser, on the site, with other people in the same world. Three.js or React Three Fiber for the picture, Rapier for physics, a WebSocket room on the VPS for the "other people" part, Supabase for anything that has to survive a refresh. Nobody installs anything. You open a URL and you're in.
Three starting ideas, honest pluses and minuses, then a pile of fresh ones that fit a shared website where anyone can drop in.
Battle royale
A hundred people parachute onto one map, the circle shrinks, last one standing. The Fortnite shape, but in a tab.
Pluses
- Everyone already knows the rules. Zero tutorial.
- The "shrinking circle" is the best pacing device ever invented. Every match ends in a climax by design.
- Great stream content: one camera, one survivor, chat screaming.
- Spectating is free. Dead players keep watching, so the room stays full.
- Loot, skins, seasons. The monetisation is well trodden.
Minuses
- It needs a crowd. A battle royale with six people is a sad hide-and-seek. Matchmaking at 3 a.m. Paris time is an empty lobby.
- Netcode is the whole game. Hit registration, lag compensation, cheating. Browsers make this harder, not easier.
- Assets. A hundred players, a big map, guns, animations. That's a studio's worth of content, and a tab has a tight memory budget.
- It is a crowded genre. "Fortnite but worse and in a browser" is the review we would get.
- No Paris in it, no story, nothing that is ours.
Verdict: the mechanics are gold, the scale is the problem. Keep the circle, shrink the player count, change what "fighting" means. See the fresh ideas below.
Autonomous AI Paris
A slice of Paris, say one arrondissement, running 24/7 on the VPS. Virtual humans with names, jobs, apartments and opinions. They talk to each other, open cafés, close cafés, protest, vote, and eventually run the mairie. The city changes because they decided it should. Visitors watch, poke, and sometimes get elected.
Pluses
- Nobody has this. Every 3D city is a backdrop. Here the city is the game.
- It fits the site's whole thing: agents that plan, argue and act. The Orchestra already does that with text. This gives it a body.
- It never ends. The world is different tomorrow, so people come back.
- Emergence is content. "The 11th voted to ban cars and now the bakers are striking" writes itself as a post, a stream, a thread.
- Cheap to enter as a visitor: you don't play, you visit. Walk around, read the graffiti, sit in the council.
Minuses
- LLM calls cost money and a thousand citizens thinking every minute is a bill, not a game. Most citizens have to be cheap scripts with a few expensive brains on top.
- Simulations drift into boring or into chaos. Someone has to tune the thermostat forever.
- "Watch AI do stuff" is passive. Without a lever for the visitor, it is a screensaver.
- Government sim can get weird fast. Virtual humans saying real-world political things on a site with a real name on it needs guardrails.
- Rendering Paris, even one arrondissement, is a lot of triangles. Low-poly or stylised is the only honest way to do it in a browser.
Verdict: the most "us" idea. Ship it small: one square, twenty citizens, one mayor, one lever for visitors. Grow from there.
Skate game in Paris
Skate. Paris. République, Bercy, the Palais de Tokyo ledges, the Seine quais. Trick system, lines, replays, a soundtrack.
Pluses
- Paris is genuinely one of the best skate cities on earth, and every skater knows it. The spots sell the game.
- One player is enough. No lobby problem. You can play alone on a Tuesday.
- Skate games are about feel and replays, and replays are shareable clips. Built-in TikTok pipeline.
- Small maps work. One plaza is a full game if the physics feel good.
- It photographs well. Screenshots of a low-poly République at golden hour are the marketing.
Minuses
- Feel is everything and feel is hard. Skate physics takes months to get to "not embarrassing" and years to get to "good".
- Keyboard skating is worse than controller skating, and a website means keyboard first.
- Content is spots. Every spot is a modelling job.
- Multiplayer in a skate game is mostly "free skate together", which is nice but not a reason to log in.
- Session Skate and Skater XL exist. The bar for "skate sim" is set.
Verdict: lovely, doable at small scale, but the shared-website angle is weak unless we invent one. Ghost lines and spot building fix that (below).
Fresh ideas that fit a shared website
The common test: does it work when one person shows up, and does it get better when a hundred do? Ideas that pass both.
Pigeon Royale
Battle royale, but you are a pigeon over Paris and the circle is a hawk. Forty pigeons, thirty seconds to find a croissant, last bird flying wins. Matches are two minutes so an empty lobby fills fast, no guns so no netcode nightmare, and pigeons are three hundred triangles. Rooftops, balconies, the inside of Gare du Nord. Chat throws bread.
The Mairie
The AI Paris sim, with one lever: the visitor is a citizen too. You get one vote a day and one line in the suggestion box. Citizens read the box. Every Sunday at 20:00 the council sits, live on stream, and votes on the top three proposals. If they pass, the city changes on Monday: a bike lane appears, a café closes, a statue moves. The site shows a live camera on the square and a "what changed since you last came" card on the front page.
Ghost lines
Skate game, asynchronous multiplayer. You land a line at République, it is saved as a ghost. The next visitor sees your ghost skating the plaza, can race it, can try to beat it. A hundred ghosts on one plaza on a Saturday night looks like a session. Nobody needs to be online at the same time. Leaderboard per spot, replay button on every ghost, share a link to a line.
Spot builder
Same skate map, but the plaza is empty and visitors drop the obstacles. Ledges, rails, a bench, a fountain. Each object stays for a week unless enough people vote to keep it. The map is whatever the crowd built. Bad spots die, good spots get famous. Paris-shaped Minecraft for skaters.
One arrondissement a week
The AI city, built in public. Each week the stream builds one new block: Alex models the buildings live, chat names the streets, citizens move in on Friday. Twenty weeks, twenty arrondissements. The site shows the map filling in. People who were there for the 3rd get their name on a plaque in the 3rd.
Chat is the weather
Whatever the sim does, stream chat controls the sky. Enough people type "rain" and it rains, and citizens go inside, and the cafés fill, and the economy shifts. A dumb lever that everyone understands, that visibly moves the world, and that costs nothing. Add "strike", "heatwave" and "Bastille Day" as premium buttons.
The Périph
Racing, not skating. Thirty-five kilometres of ring road, loop it at night, low-poly cars, drift the Porte de Bagnolet exit. Asynchronous ghosts again, so it works alone. Weekly time trial, live final on stream on Sunday. Chat picks the weather (see above).
Elections night
Every visitor to the AI city becomes a candidate if they want. You write one slogan, pick three policies from a menu, and the citizens decide. Real people campaign in chat for an hour, virtual citizens vote, the winner runs the city for a week and their decisions actually happen. The most "join in from a website" version of the government sim.
The stream is the map
Whatever Alex is streaming becomes a place in the world. Streaming from Japan in November: a Tokyo district appears next to Paris for two weeks, citizens can take the train there. The world follows the real life, and the site becomes the place you go to see where it went.
Rooftop tag
Parkour on Paris rooftops, ten players, one is "it", zinc roofs and chimneys, two-minute rounds. The battle royale energy without the guns or the hundred-player lobby. Pigeons from Pigeon Royale flying around for free. Fits a lunch break.
Which first
If we had to pick one to prototype this month: The Mairie, tiny. One square, twenty citizens, one suggestion box, one Sunday vote on stream. It is the idea only this site can do, it works with one visitor, and it gets better with a crowd. Ghost lines is the second: it is the most fun to make and produces the most clips.
Pigeon Royale is the wildcard. If it feels good in a weekend, it wins.