It looked like it had seen better days and was in desperate need of some tender loving care. The box was little more than a coffin. I opened it up and, just as I thought, there were various pieces missing and the board was about to disintegrate. Either someone had played this game to death or the mice had been at it. The most exciting part about the game, though, was that it didn't have any instructions. It was perfect.
The game board was covered in 20 numbers, some inside circles and some inside triangles, all connected by lines. It wasn't obvious what you were supposed to do, but I knew 30 creative minds who between them would certainly apply themselves to inventing some.
I haggled over the price and bought the game to take to school the next day. What followed was one of the most inventive maths lessons I've ever done. Try giving your class a game without rules and see what they can do.
Cost of game: 10p. Engagement and enjoyment: priceless John Dabell is a teacher trainer and maths consultant