Hi Katie,
Thanks for reaching out!
Community Events ($89) will let your users submit events from the front end of the site, which will then be displayed on your sites calendar along with the events you create yourself. You do have the option to require users to be logged in to submit events, which gives you come control over who can create events.
Another useful extension would be Event Aggregator ($89), which will let you import events (manually or on a schedule) from other multiple sources such as Facebook or a Google calendar.
We do offer full refunds within 3o days of purchase if you’re not satisfied with our products, so feel free to test them out and see if they’ll work for you! Please let me know if you have any other questions.
Thanks,
Jennifer