Looks as though the Event Tickets add-on (4.0.4) is breaking the Events view (in 4.0.5). That is, the list of events no longer displays.
Oh, I should have mentioned that it mostly works!
Thanks, Rob and Leah. Terrific.
If anyone wants a temporary fix for your main headers, try this in your style.css
header.entry-header { display: block !important; }
Don’t forget to take it out once Tribe issue a more permanent solution.