Including a PHP file in Drupal via BLOCKS, or REGION
You need to create a block template in your themes template folder.

To do this, you would create a new block, in Structure > Blocks, give it a bit of dummy content and save it in a region.

Then inspect the ID of the block in the source, or in Chrome Dev Tools, or Firebug, it should be something like block-block-1

In your themes template folder, copy the file block.tpl.php and rename the copied file block--block--1.tpl.php 

In that file, you should see something like...

&lt;div class="content"&lt;?php print $content_attributes; ?&gt;&gt;
    &lt;?php print $content ?&gt;
  &lt;/div&gt;


Just replace the &lt;?php print $content ?&gt; with your content from ads.php

Then, in Performance > Development, flush the cache, and you should see your template replace the content of the block you created.