I would love to have an autogenerated iCal/Google Calendar feed created with all events I mark Interested in that I can import to my Google Calendar or other calendar app.

For example many services let you create a universal iCal calendar feed URL that can be imported into gCal, iCal, Outlook, etc.

https://calendar.google.com/calendar/ical/72bj8rtor1lfioi0%40group.calendar.google.com/public/basic.ics

This would be great for increasing user participation because I think a lot of people simply forget when the events are and the notification system is a bit weak. A calendar feed would help people to actually plan to be around for the event. More participation would allow more events to be planned and grow the platform.