Where the money actually goes.

• 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

  Try itHow it plays, and how to run it
• 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

  Try itHow it plays, and how to run it
• The reserve fund

  Three trustees, one small charity's thirty thousand pounds, and a third each to place: the building society, government bonds, or shares in the company everybody is talking about. A quiet year puts the share-heavy funds on top. The same decision, in the year the news lands, puts them at the bottom. Beside every profit is the swing that fund was carrying — the same number in both years, and printed before either of them happened.

  Groups of 3 · About 19 min · 2 acts

  DiversificationRisk and return

  Try it

• One budget, two assets, your call

  Students divide a fictional budget between two assets, inspect risk across a probability table and discuss one common illustrated outcome. They then revise for a stated minimum-variance objective and compare their two decisions. The teacher advances each slide; shared counts and private exact results remain separate.

  Up to 600 people

  DiversificationRisk and return

  PlayingHow it plays, and how to run it

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