My three sons were fascinated by catapults and trebuchets for some reason. During summer vacations they seemd to always be trying to make one of these with various materials and varying degrees of success. But they never tired of the quest. I suspect they were not alone–we see the “punkin’ chunkin'” trebuchets on tv sometimes.
They all became engineers, but I doubt that everyone who tried to make these contraptions became engineers. If your family want to try this cardboard one, it’s a good way to get started in this “hobby.” Just be sure they don’t break anything valuable or hurt anybody.
Click title for link at Instructables. There are similar projects on the right sidebar there to try too.