ruby script/plugin install git://github.com/aaronchi/disable_timestamps_for.git

Just add disable_timestamps_for to any of your ActiveRecord models and define the field or fields for which you would like to skip timestamping.

  class List < ActiveRecord::Base
    disable_timestamps_for :position
  end
	
  class ListItem < ActiveRecord::Base
    disable_timestamps_for [:position, :list_id]
  end

Rails will now disable timestamping on updates if these are the only fields that have changed.

There is currently no advanced documentation for this plugin.