Emacs actually has built in support for the unix calendar format and the official distribution has import and export utilities for ical files so you can handle/

Emacs actually has built in support for the unix calendar format and the official distribution has import and export utilities for ical files so you can handle/generate invitations. I keep it in the same git repo that I have my org files in. I'm actually a vim user (and have been since I was ~12.) I just use Emacs because it's where all the good PIM tools are for Linux.