Before you disable the email communication from an event, it might be a good idea to contact the event host to let them know that they are sending too many emails for your preference. Event hosts don't want to overcommunicate, and will improve their communication strategy if their attendees tell them!
From the main page of the event:
Select Account>Edit My Profile in the upper-right corner of the screen:
In the Edit My Profile Menu, click the Preferences tab:
Check the checkbox for "Do not send me any email" and Save.