Firstly you will need to split your cohort into groups of approx 4-5.
Each group will need to have exactly the same resources. The same number of marshmallows and the same number pieces of spaghetti. If you have a large group this can therefore take a little preparation before the event.
The idea for this activity is to see which team can build the tallest tower using just marshmallows and spaghetti. How each team does this is up to them. They can break the spaghetti, chop the marshmallows etc.
The tallest tower that is freestanding is the winner!
An extension or variation of this activity is who can make the longest unsupported bridge. The measurement should be taken between the two support towers.