_menu_curators.html.erb

<small><ul>
  <% @curators.each do |member| %>
    <li><%= member.person.name %></li>
  <% end %>
</ul></small>

plots_controller.rb (private method and before_filter)

before_filter :get_plot_curators

private

# add to existing private methods
def get_plot_curators
  @curators = Membership.find(:all, :conditions => ['plot_id = ? AND joined_on IS NOT NULL',  @plot.id])
end