I always liked reading The Giving Tree and I know a lot of my students know about the story. I adapted the story based on the book so that my students could start looking at the preterite and the imperfect and start seeing when to use either. I usually teach the preterite and the imperfect along with the acronym BIC for the preterite as in Beginning Actions, Interrupting Actions and Completed Actions. I use DRUWIT for the imperfect Descriptions, Repeated Actions, "Used to", Was or were happening, Internal emotions and Time/age/weather.
After the students have to create a timeline to retell the story and to show how the preterite moves the story along.