has_many :events, :as => :eventable (Story)
has_many :events, :as => :eventable  (Alert)
belongs_to :eventable, :polymorphic => true (Event)

Stories and alerts have the same fields

Events table has
id|eventable_type|eventable_id

yet....

>> story = Story.find(:first)
=> #<Story id: 1, title: "story1", created_at: "2008-05-02 23:05:50", updated_at: "2008-05-02 23:05:50", active: true, parent_id: nil>
>> alert = Alert.find(:first)
=> #<Alert id: 1, title: "WooWoo", content: "Alert aler!", created_at: "2008-05-03 14:35:21", updated_at: "2008-05-03 14:35:21">
>> story.events.new
=> #<Event id: nil, week_id: nil, day_number: nil, eventable_type: "Story", eventable_id: 1, created_at: nil, updated_at: nil>
>> alert.events.new
NoMethodError: undefined method `events' for #<Alert:0x246a51c>