Gloriously spring like day in the woods.
Younger kids showed perfectly what magic develops when you leave them to thier imaginations. 
A complex economy built around the "goldmine" . A shop, with salesmen, suppliers, miners and quality checkers, buyers. Traders who set up a rival shop after realising they were losing out (making a profit is kinda unfair I guess!) So now we've got trading, sales, and customer offers. It's tiring work so eventually retirement and selling up.
Trading games are so good for kids.

Big kids needed a chill afternoon. Some of them have ridiculous schedules of school and activities and a fair bit of pressure. A few were saying thier only downtime is in the car :( 
So we chilled in the sun, ate biscuits and drank hot chocolate. with space to do nothing, wander off and climb trees (extra), build dens and throw rocks as felt good.