Mozillians will want to look for events based on their specific areas of interests, teams, projects and products. The Phonebook's curated groups can help Mozillians better search filter out specific hosts of events. This implementation is much like the Taskboard's approach with a simple list of Curated Groups.
Events generally are located in a physical location. New/Potential as well as Active/Core Mozillians will want to find events in their specific geographic locations. Using Open Street Maps, the app should allow users to type in a street/city address and zoom in & out of a small geographic map (Look at Yelp for examples).
Mozillians should be able to search for a specific set of events occurring on a single date or within a specific set of days. A simple date range picker will suffice here.
Other than date range, location, groups and skills filters, Mozillians will also want to look for events based on title/summary and description. Multiple terms can be used to filter down events results.
Mozillians may want to keep tabs of events through their own calendar applications, so they'll need a calendar linked to the Mozillian Events Manager. On any search result page, the app will offer a link to download the .ics file used the newly filtered results.