Yes. This is definitely possible using GetAppointmentRequest and CreateAppointmentRequest. If you're doing the script in Python you can use the Python Zimbra-Library for easy use of the API. (shameless self-advertising ;-) )
I'm willing to share. Just tell me, what you need.
That is brilliant! Thanks for sharing. I bet, that you could also support IMAP users by using nginx with an intelligent proxy configuration. Still, Outlook users would be kept out, but who needs those ones, right? ;)