18. Summer camp
You can organise a little summer camp and have kids participate in treasure hunts. You can hold it over a couple of days or even have it run a week.
Set up activities based on the age of the kids. Get parents involved if the kids you are handling are too young to manage on your own.
19. Teach a craft
No one is ever too young to teach. If there is a craft you are really good at why not get paid to teach it to someone. Bluprint is an online platform that teaches you everything from cooking, sewing, and crafts. You can access the videos here for free. This may be of good help while teaching your skill to others.