We had some group challenges against the clock, as part of the Goldilocks book we were reading. The boys were racing against the girls to see who could pick up the most jewels with tongs. The teams took it in turns with one person being in charge of the time, one person writing down the score and one person picking up the jewels and counting them. We got more and more excited but in the end the girls just won with 34 jewels.
We tried building a tower from cups as well and drawing round to measure them, but the towers kept falling over when we were balancing the cups on top of each other.