Hi Will,
This is an interesting question. We do have a Community Events add-on, which allows users to add events from the front-end of the web site, would that do what you need it to do?
If you are thinking to have users login and use your WordPress back end to add events to calendars, you could always give them each their own Category. There are some tutorials on our site, as well as a themer’s guide, to customizing the look and display of the categories, which might be useful to you when it comes time to install and set everything up.
Does that answer your question? If not let me know!