Jamis has a nice article on how to Harness SQL. I personally love ActiveRecord but I agree that you should use AR as much as you can, but trying to force all your work into AR even though it may not fit is a mistake.

def instantiate
  list = TodoList.create(:name => name, :description => description)

  TodoItem.connection.insert <<-SQL, "Populating items"
    INSERT INTO todo_items (todo_list_id, content, position, created_at)
      SELECT #{list.id}, content, position, UTC_TIMESTAMP()
        FROM todo_item_templates
       WHERE todo_list_template_id = #{id}
  SQL

  list.todo_items.reset
  list
end