gistfile1.rbx

class Conference
  has_many :attendees, :class_name => 'Person', :through => :attendance
  
  def Conference.next_upcoming
    self.find!(:first, :conditions => ['starting_at > ? and visibile = ?' Time.now, true])
  rescue RecordNotFound
    self.most_recent
  end
  
  def most_recent
    ...
  end
end

class Attendance 
  belongs_to :conference
  belongs_to :person
end

class Person
  has_many :conference, :through => :attendance
  
  before_create :salt_password, :encrypt_password
  
  def salt_password
    ...
  end
  
  def encrypt_password
    ...
  end
end


class ConferencesController
  def current
    Conferences.next_upcoming
  end
end

class AttendencesController
 def  create
   Attendence.create(params[:attendence])
 end
end