I have begun to make a monthly calendar detailing some special events during the month. I then post these around the school as decoration. Feel free to take and modify as you see fit. I like to try an included religious days for those who are interested in different types of celebrations. No one in my school had even heard of Lent or Ramadan but the teachers seemed to be particularly interested in it; bafflement even more so!
Since I'm British and Swedish, I elected to include events related to those countries - stuff that the students can later ask me about. Since I'm based in Miyagi prefecture I also added a festival in Aomori and will do more Tohoku-based festivals in the future to help students learn about their own area!
The students recently did chōjū-giga (鳥獣戯画) in art class and I was able to partake since I was free. While I'm not good at it, I love the art-style! I tried designing some comical scenes surrounding the events on the calendar.
If you also like the illustrations and want to use them you can find them here: https://chojugiga.com/