AdminPrePageHead

From LordMattWiki

Passes one array which contains

 'extrahead' => &$extrahead 
 'action' => $this->action

$extrahead by default is empty and is echoed into the HTML stream just before the </head> tag.

The action variable contains the instruction to the admin area (the whole area can listen in)

In theory you could "hijack" the admin area for a given event and build it yourself ending with a php teminator... how well this would work is another mater.