Your child doesn’t need another activity. They need a reason to keep going.
The toys are there. So are the books, the LEGO, the craft bin and the activity pads. And you still hear “I’m bored” five minutes after you suggest one of them.
Most activities give a child a task: finish the maze, find the words, color the page. Nothing depends on finishing it, so the motivation ends up coming from you. “Try one more.” “Just finish this page.”
A mystery gives them a question instead. Someone took the dinosaur egg from the Maplewood Museum. There are five suspects, and one of them did it. Every puzzle your child solves tells them something new about who, which gives them their own reason to turn to the next page.