This is a very simple plugin for the Cacti Plugin Architecture created by Jimmy Smith for Cacti 0.8.x (0.9.0 is slated to have a new plugin system from the start). It's just about the smallest plugin you can have - it lets you have a page of arbitrary HTML content behind one of the tabs at the top of the page.
You could use this to integrate other tools into Cacti - say you want to have links to Smokeping, or Request Tracker, or Nagios...
Latest Version: 0.3
Screenshot: