Not so much a game but a great way of introducing planning and problem solving for older children which is ideal for an outdoor activity but can also be carried out in the classroom if you have room.
Children should work in groups of 6 ideally but 5 or 7 is OK
Provide for EACH child one plastic cup, two drinking straws, a 60 cm length of string, a cotton wool ball, a large rubber band. Add a lego figure per team for good measure if you like. (If there are more or less than 6 kids, make sure they only have 6 cups between them.)
The task is to make a pyramid out of the cups without touching them.
Here is an example of 10year olds doing this.