Late night events:  Previously could not be created due to validation from_before_to. PT: 75084268 

Can now create events that start just before midnight UTC and end after midnight.  PT: 
Good idea.  We could have start_datetime and event_duration...  its really  6 of one, half-dozen of the other. It will be easier to combine event_date and start_time into a single field, in any case.  
I have the following code in the hookup_tables PR to adjust the end_date accordingly (for internal calculations, end_date isn't stored in the database).
  def end_date
    if (end_time < start_time)
      return (event_date.to_datetime + 1.day).strftime('%Y-%m-%d').to_date
    else
      return event_date
    end
  end
This is related to your comment about "complex and non-intuitive rules".
If we change the approach, then I need to change my PR... and much more.
This ties in with views for creating/editing events for the existing events page, as well as queries to get active and pending and expired events.  
Also, it ties in with the goal to use only UTC timedates in the ruby/rails code, and to convert to/from localtime in the browser/js.  

I hope that you can accept this change for now, and submit the broader "refactoring event time"  story into Pivotal for later.  It isn't a "final" fix, but it's better than nothing.  Otherwise, some events just won't be able to be submitted until we get around to implementing this refactoring story, which might take weeks.