The Diary of a Sixth Grade Ninja by Marcus Emerson a one hour read
This is the story of Chase Cooper who has moved across town and now goes to a new school. Fortunately, his cousin also attends the school and she is willing to help him fit in. So they have the laziest coach who takes them outside for gym and then he stretches out in a lawn chair for a nap. Chase and his cousin discover a band of ninjas hiding in the wood just beyond the playing fields. The ninjas are students who apparently slip away from gym class change into ninja outfits and hang out in the woods until the bell rings. The issue is, are they good ninjas or bad ninjas.