MEGA MENU please help trying to assign it the right region but no luck :(
It depends a bit on your theme but for bartik here is answer:

In theme info file add this:

regions[my_custom_region] = My Custom Region


Then copy page.tpl.php from the base theme, or else from modules/system directory into your theme's folder. Open it up, and look for the bit where it prints out the main menu. It will be something like this:

&lt;?php if ($main_menu || $secondary_menu): ?&gt; 
      &lt;div id="navigation"&gt;&lt;div class="section"&gt; 
        &lt;?php print theme('links__system_main_menu', array('links' =&gt; $main_menu, 
'attributes' =&gt; array('id' =&gt; 'main-menu', 'class' =&gt; array('links', 'inline', 
'clearfix')), 'heading' =&gt; t('Main menu'))); ?&gt; 
        &lt;?php print theme('links__system_secondary_menu', array('links' =&gt; 
$secondary_menu, 'attributes' =&gt; array('id' =&gt; 'secondary-menu', 'class' =&gt; 
array('links', 'inline', 'clearfix')), 'heading' =&gt; t('Secondary menu'))); ?&gt; 
      &lt;/div&gt;&lt;/div&gt; &lt;!-- /.section, /#navigation --&gt; 
&lt;?php endif; ?&gt;


Remove this bit, then add this in its place:

&lt;?php print render($page['my_custom_region']); ?&gt; 


Now clear your cache and place your block inside it.

Rename the my_custom_region to whatever you like, but make sure it is same in info file and page.tpl file.

If you don't want to replace the main menu then you can just paste the new code underneath the main menu, and in the menu settings UI select no main menu to hide it.