Counting the Omer
While we're noting day 33, it is worth mentioning that there is a lot to say about the count itself. Lesson plans could focus around the specific Biblical content about the counting, around questions of what the actual mitzvah to count consists of, or on the focus on new versus old grain. Below is the verse from Sefer Vayikra that describes the process of counting.
On the most basic level, counting the "omer" - a quantity of grain - leads up to a grain offering (and the holiday of Shavuot!). There are many sources that delve into the deeper significance of this count. Sefer HaChinukh emphasizes our eagerness to count up to the day we receive the Torah and the Kabbalistic tradition associates different sefirot (Kabbalistic spheres) with each day, as pictured below. Even younger students could be engaged with lessons around broader questions about counting (what else do we count, what's the significance of counting something, etc.), and there are many sources about the kabbalistic and/or spiritual significance of counting the days between Passover and Shavuot.
Mourning During Sefirat HaOmer
The Omer period became a period of mourning because Rabbi Akiva’s students died from a plague during this time. The plague ended on Lag Ba'Omer (33rd day of the counting of the omer) which turned the day into a day of celebration. Educators might choose to focus on the specifics of the mourning practices, or more broadly around themes of respect and treating others well that are surfaced in this story.
Rabbi Shimon bar Yochai Enters the Story
Rabbi Shimon bar Yochai was a student of Rabbi Akiva. He died on Lag Ba'Omer and is buried on Mt. Meron in northern Israel (pictured below). His life is remembered and celebrated on Lag Ba'Omer.
Lag Ba'Omer Song
This song, written by Shimon ibn Lavi (1486-1585), is often sung on Shabbat in Sephardic communities. It is widely sung, in all communities, on Lag Ba'Omer. Teachers might pair this with video clips or photos from the celebrations at Meron, or clips of other Lag Ba'Omer songs.