Maybe contact your local YMCA or YWCA and see if they have an after school program that needs help. You might be able to implement your own ideas into their program. Just a thought.
My DS23 worked at the YMCA during his summer break when he was in 10th and 11th grade. He and a few other teens worked all day on weekdays at the summer camp and the kids just loved them. Especially the little girls!

I know they are usually looking for people who enjoy working with young children.