It would be great to add custom tags to calendar days (instead of creating events). For example:

Friday, August 7. Term 3, Week 3

I work at a school, so seeing the current term and week while planning would be really helpful.

Since the tags would be custom, they could also be used for other purposes, such as project phases, sprint numbers, or campaign periods. Ideally, they'd also be visible in the board view for quick context without opening the calendar.