Have you ever read this book?
It's one of our favorites. Again, while my mom was here, she took the boys to story time and checked it out. One afternoon we acted out the story.
My boys loved it! We would narrate the story and they would act it out. My 4-year-old thought it was fantastic and my 2-year-old was an excellent monkey!
When my mom took them to the park they acted out "The Three Billy Goats Gruff" and "The Three Little Pigs." My 4-year-old loved it so much that he asked grandma to make him a bear mask so he could play "Goldilocks and the Three Bears."
Easy. Simple. Fun.