Markets that run on your students' choices.

• Closing time at the market

  Buyers and growers submit sealed offers. Reveal the market, then reuse those exact orders under a minimum selling price. Each phone shows its own trade or why it stayed unsold. Compare who benefits, who cannot find a buyer, and why unsold crates are not government purchases.

  Up to 600 people

  Supply and demandPrice controls

  PlayingHow it plays, and how to run it
• The stag hunt — one day, two ways to spend it

  A stag needs both of you on the ridge all day and the share that comes home is five suppers. A hare is three, it is yours alone, and you can take one at any point in the day. Neither choice is right by itself: what you should do depends entirely on what you think the person beside you is about to do. Played twice, the second time when being the one who stayed actually costs you four suppers out of an empty larder.

  In pairs · About 30 min · 2 acts

  Coordination problemsRisk dominanceNash equilibrium

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• Ten rounds in the pot

  Ten tokens, ten times. A token you keep is worth one to you; a token in the pot is worth half a token to every single person in the room. The pot is better off the more goes in and you are better off the less you put in, both at once — and the board builds the room's own curve as it plays, round by round, which is the thing a final number cannot show you.

  Up to 600 people · About 11 min

  Free ridingDominant strategiesRepeated games

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• One lot, and the best loser sets the price

  One lot, one sealed number each, sold to the highest bid at or above the reserve — and the winner pays the SECOND-highest bid, or the reserve if that is higher, rather than their own. The room is told the price; each bidder is told privately what their own bid did. The debrief is the part that lands: your number decided whether you won and never what you paid, so no bid beats the honest one — which is exactly what stops being true the moment a winner pays their own.

  Up to 600 people · About 10 min

  Second-price auctions

  Try itHow it plays, and how to run it
• Spend the neighbourhood fund

  £100,000 in the fund, £155,000 of schemes, and a price on every one of them where the room can see it while it ranks. The fund is spent straight down the room's combined order and the board draws the line where the money ran out. The lesson is in what is left in the pot: spending a fixed fund down a ranking is not the same operation as getting the most out of it, and the room's own ballot decides how many schemes end up standing.

  Up to 27 people · About 10 min

  Budget constraintsPreference aggregation

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• Ten coins and nobody can stop you

  One of you holds ten coins and decides how many the other gets. They have no move at all — no accepting, no refusing, no comeback. Two rounds, and the room is re-dealt between them, so nobody ever decides about the person who decided about them. The room sees the whole distribution of what was given when nothing could be done about it and nothing could be bought with it.

  In pairs · About 20 min · 2 acts

  AltruismFairness norms

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• Twenty coins, take it or leave it

  One of you divides twenty coins; the other takes the split or refuses it — and refusing leaves BOTH of you with nothing. Three rounds against three people you will never play again. The room sees every offer it made, which ones died, and how many coins it destroyed to say no.

  In pairs · About 45 min · 3 acts

  Fairness normsCostly punishment

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• Send it and see what comes back

  Whatever you send your partner is multiplied on the way over, and then it is entirely theirs — nothing makes them send any of it back. Round one is trust with nothing behind it: nobody knows a thing about the person opposite. Round two changes three things at once — the sides, the multiplier, and the fact that you now know them — and the debrief says so, because a board that moved for three reasons cannot be read for one.

  In pairs · About 30 min · 2 acts

  Trust and reciprocityRepeated games

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• Two factories, one market, and the price you both set

  You and one rival make the identical crate and sell into the same demand, so the price is not yours to set — it is whatever the two of you produce between you. Make a lot and you sell a lot cheaply. The room sees where every market landed between what one seller alone would have made and what a price war would have, and what each of them earned for it.

  In pairs · About 20 min · 2 acts

  Imperfect competitionNash equilibrium

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• Two sellers, identical crates, and whoever is cheapest takes the lot

  Your crates are identical, so nobody has any reason to pay you more than they pay your rival. Undercut by a single pound and you take every buyer; tie and you split them. There is no safe high price, and the room watches two firms — just two — drag the price all the way down to what a crate costs to make.

  In pairs · About 20 min · 2 acts

  Price competitionMarginal cost

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• One of you builds the factory first

  One firm commits to its production and cannot take it back; the other sees that number and then decides. Nobody forced anybody — but committing to a large run leaves the follower nothing better than a small one, and the theory says that is worth exactly double. Played twice, with the sides swapped, so everybody gets to go first.

  In pairs · About 25 min · 2 acts

  First-mover advantageImperfect competition

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• Four boats and a bay that belongs to nobody

  Four skippers work one bay, which stands about twelve strings of pots before it stops coming back. Shooting five strings beats shooting two every single time, whatever the other three do — and if all four shoot two, every boat lands twice what it lands when all four shoot five. One boat hauling costs the others nothing; the second takes it off every other boat, the two who worked steady included. Then it is played again, the year the bay does not come back.

  Groups of 4 · About 19 min · 2 acts

  Common-pool resourcesExternalitiesDominant strategies

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• What is a flat worth to you?

  Six identical flats, more people than flats, and everybody writes down the most they would pay. The six highest bids at or above the landlords' reserve are housed, and every one of them pays the best bid that MISSED OUT, or the reserve if that is higher. Then three become short-lets and the same room bids afresh for the other three. Held to the same bids, the rent could not have fallen: the best losing bid would come from higher up the room's own list. No winner chooses the rent, and the people scarcity costs most are the ones priced out of the market.

  Up to 600 people · About 19 min · 2 acts

  Supply and demandPrice discovery

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• Three cars on one forecourt

  You hold a good car, a fair one and a banger, and room on the forecourt for exactly one. The buyer is not being cheated — they genuinely value any car at half again what its owner does. They just cannot tell which is which, so they pay one price for the average of what is out there. Putting out your worst car beats putting out your best, every time, and an honest seller is paid an average that other people's bangers dragged down. Then the cars are inspected.

  Groups of 3 · About 19 min · 2 acts

  Adverse selectionAsymmetric informationDominant strategies

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• You are the market

  Students become buyers and sellers, read private value or cost cards and submit sealed offers. The room sees the curves those offers create; each phone identifies its own ordered step and trading outcome. Change the seller-cost schedule, collect fresh offers and compare both markets. Discuss how costs, choices and participation may explain the differences without assuming a direction of price change.

  Up to 600 people

  Supply and demandPrice discovery

  Try itHow it plays, and how to run it
• Who really pays a tax?

  Buyers and sellers hold private value and cost cards, then submit one sealed set of orders. The room sees the demand and supply curves those orders make. Holding the orders fixed, compare a per-trade tax collected from sellers with the same tax collected from buyers: the posted price changes, but buyers pay the same all-in amount and sellers keep the same net amount whenever trade occurs. These are labeled hypothetical outcomes, not a second round of bids. Discuss what could change if people bid again under the tax.

  Up to 600 people · About 4 min

  Supply and demandTax incidence

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• Tenants and landlords

  Tenants and landlords hold private value and cost cards, submit sealed offers and see the market those orders create. A second market introduces a rent cap and collects fresh bids and asks while keeping the same cards. Compare rent, trades and any buyers turned away at the cap; each person sees their own accepted offer and outcome privately. Discuss whether the cap bound and how changed offers may also explain differences between the two markets.

  Up to 600 people · About 13 min

  Supply and demandPrice controls

  Try itHow it plays, and how to run it

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