non event_calendar

What am I missing here, trying to get the event_calendar plugin working
with my existing app. Have installed the plugin, which I guess is a good
start, then this...

class Booking < ActiveRecord::Base
  has_event_calendar :start_at_field => 'arrival_date', :end_at_field =>
'departure_date'

Route...
  map.availability_calendar '/availability_calendar/:year/:month',
                            :controller => 'properties',
                            :action => 'availability_calendar',
                            :requirements => {:year => /\d{4}/, :month
=> /\d{1,2}/},
                            :year => nil,
                            :month => nil

Action in controller....
  def availability_calendar
    @month = (params[:month] || Time.zone.now.month).to_i
    @year = (params[:year] || Time.zone.now.year).to_i
    @shown_month = Date.civil(@year, @month)
    @event_strips = Booking.event_strips_for_month(@shown_month)
  end

View .....
  foo
  <%= event_calendar %>

Result....
  undefined local variable or method `event_calendar' for
#<ActionView::Base:0x102e77220>

Interestingly if I change this...

class Booking < ActiveRecord::Base
  has_event_calendar :start_at_field => 'arrival_date', :end_at_field =>
'departure_date'

to simply

has_event_calendar

I get this error...

Mysql::Error: Unknown column 'end_at' in 'where clause': SELECT * FROM
`bookings` WHERE (('2010-10-30 23:00:00' <= end_at) AND (start_at<
'2010-12-05 00:00:00')) ORDER BY start_at ASC

Which suggests the plugin is working it just doesn't like my customised
start and end syntax?

Hmm, thinking out load here - I just created a fresh test app with just
the plugin and it worked.

dates are all of type DATETIME.

My dates of of type DATE - maybe that's the problem.

Ignore me.

I needed a helper like this..
All good - :-), it looks Great.

module CalendarHelper
  def month_link(month_date)
    link_to(I18n.localize(month_date, :format => "%B"), {:month =>
month_date.month, :year => month_date.year})
  end

  # custom options for this calendar
  def event_calendar_opts
    {
      :year => @year,
      :month => @month,
      :event_strips => @event_strips,
      :month_name_text => I18n.localize(@shown_month, :format => "%B
%Y"),
      :previous_month_text => "<< " +
month_link(@shown_month.last_month),
      :next_month_text => month_link(@shown_month.next_month) + " >>"
}
  end

  def event_calendar
    # args is an argument hash containing :event, :day, and :options
    calendar event_calendar_opts do |args|
      event = args[:event]
      %(<a href="/events/#{event.id}"
title="#{h(event.name)}">#{h(event.name)}</a>)
    end
  end
end