Is there any way to email all attendees of a calendar event?

Yes, you can email all attendees of a specific calendar event. To do this, you can right click or double click on a specific calendar event and then click on the attendees screen. Once on the attendees screen you can then click on the 'Email all attendees' button and a new email compose window should open up with all attendees email address populated in the 'To:'  field.