I tested the zoho.calendar.createEvent task (ref) and have some observations and questions.
Documentation: Instruct users to create a calendar name in Z Cal or use an existing one. Also, it would be helpful to provide examples of converting Z Creator date-time into Z Cal accepted format.
There should be a way to pull a list of calendar names to populate a drop-down field.
Rich-text in descriptions not working:

I assume there will also be ways to edit or delete events?
Cheers,
John Whitney