We enjoy the occasional creative science challenge. For this challenge each child had a bunch of straws, a little clay, and a measured piece of masking tape. They had a time limit to build the tallest structure possible.
Little girl had her structure built first. Once she declared she was done, I measured the height.
The boys attempted to beat her height before time ran out. In the last few minutes my younger son finished a stable structure that was about 12 inches higher.