When viewing any event, and logged in as a manager, you can click the 'Event Dashboard' button in the right-hand sidebar of your event under 'Manage this event', to see a database of all your members who have responded to the event. Click 'Attendees' to view the database.
On the left hand side of this page, you can see all the different RSVP's for the event ('Yes', 'Maybe' or 'No') as well as tickets purchase and registrations if that is how you have configured your event. Beneath these links is an 'Export' link.
This page contains options to choose what file type to export your data in, and whether to export all yes responses, or all registrations.