How to display an "Out of Page" (PopUp) ad from Google DFP on a Drupal 6 site?
Looks like I solved it. Below is how ...

Finally got the process of creating a pop up on DFP figured out, now onto the Drupal part of it. https://productforums.google.com/forum/#!category-topic/dfp/inventory-management/dfp-small-business/e4vUwjgd4lk

UPDATE:

Got it working this way... 

OK. Looks I mostly have it.

Just bypassed the Google Admanager module and generated a tag from the ad unit page. Then I put it in my theme page.tpl.php header enclosed in this (to make sure it is only front page):

&lt;?php if ($is_front) { ?&gt;
&lt;script&gt;......&lt;/script&gt;
&lt;?php } ?&gt;


And then put the rest in the block with php enabled. I also made sure to remove the adslot generated other than the popup.

Hackish but it does the trick.

But if anyone knows how to make it work with Google Admanager, would love to look at it.