Many customers use a combination of Facebook Events, iCal Importer, and the CSV importer built into The Events Calendar to manage importing events from outside sources into WordPress.
With version 4.3 of The Events Calendar comes the launch of Event Aggregator, which combines the functionality of all of the above plugins into one service—along with some additional features and capabilities, too. For example, Meetup.com will now be available for importing events into The Events Calendar—something our plugins have never supported thus far!
A key feature of Event Aggregator is that it runs entirely on our own servers. Say goodbye to limitations with Facebook Events when importing from a large number of Facebook pages, and to significant site slow-downs whenever you perform imports—Event Aggregator’s servers will shoulder the burden of processing imports for you. Performing imports will essentially have no impact on the performance of your WordPress site in the process. You can run imports from multiple sources right from your dashboard, including Facebook, Meetup, Google Calendar, iCalendar, CSV, and ICS.