The Wednesday Wars (by Gary D. Schmidt)

At first Mrs. Baker just has Holling clean erasers, but then decides to make better use of the time by introducing him to Shakespeare. And as events in the larger world during the 1967-'68 school year unfold in the background, Holling begins to learn about himself, his family, friends, and the mysterious adult world.

With the prim prodding of his dry, no-nonsense teacher, and a big dollop of help from the Bard, Holling learns to see into the hearts of others, which causes him to stand up to his overbearing father, to care for his floundering older sister when she needs him, to recognize the depth of his friendships, to see the humanity in his teachers, and ... to begin to really understand Shakespeare. This is a funny and breathtakingly moving book, because in the end there's little that's as funny and moving as growing up -- except perhaps growing into a wise and loving person.