As a previous comment suggested, some Waldorf schools have chosen to the Fourth Great Lesson, The Story of Written Language, as a MLB. So, feel free to Google these main lessons for teaching ideas. Naturally, with the Waldorf method, they would NOT be done in 1st/2nd/3rd grade as they are in Montessori.
In Montessori, these lessons are done impressionistically, as an oral story told by the teacher over the course of several days. The teacher IS expected to memorize the story (sound familiar to anyone?) and artifacts to accompany the story are placed under a long silk and revealed in turn. Many teachers also dim the lights and light a candle. The students then engage in hands-on explorations to take the stories deeper. (Again, sound familiar???? When I became a Montessori teacher, these were the lessons I was most excited about teaching, because they are so Waldorf-y in so many ways, except for WHEN they are taught.)
Overview of the Five Great Lessons
Second Great Lesson full story and suggested artifacts for storytelling from NAMC teacher training (free sample lesson)
the First is How the Earth and Universe Came to Be
the Second is How Life Came to Be
the Third is How Humans Came to Be
the Fourth is How Written Language Came to Be
the Fifth is How Numbers Came to Be
The Great River is the story of how the systems inside the human body work together (a Waldorf 8th grade lesson).
Some of these have had books written about them by Montessori teachers, like
Some books you stumble across just happen to be a great fit, like
Miss Barbara's website is a common resource for the content of the stories themselves and Pinterest (believe it or not) is full of great ideas for follow up activities. You'll find things for these lessons everywhere you go... I was literally hiking the Stonefort Trail at Giant City State Park, IL yesterday and the trail guide was step-by-step the perfect Third Great Lesson!
Here's The History of Writing from Miss Barbara's site.
We used this lesson to have students do cave painting (the virtual tour of the caves of Lascaux is amazing and the story When Cave Men Paintedby Norman Bate is the perfect accompaniment), create their own pictograms, practice hieroglyphs, learn calligraphy, and design their own fonts. We also read How the First Letter Was Written from the Just-So Stories by Rudyard Kipling (free online).
It's a fun time to revisit and enjoy alphabet books (and a great tie-in with a first grade capital letters MLB if you are homeschooling different ages).
It's also a great time to introduce conventions of speech, like spelling and capitalization rules (another tie-in, if you are teaching a second grader as well).