Although you can't add a banner ad in the traditional way to those pages, because they are list widgets, you can add a banner ad, or any other widget, to the header space of just that page. This feature is often used to add sponsorships or other focused content to pages like the Agenda, Sponsors, or Speakers.
- In the Host Tools Dashboard, navigate to the page that you'd like to have the custom header and click into it so that you can see the list of widgets on that page.
- Select Settings>Layout Options in the right corner
- Select the word Header, inside the Desktop box
- On the Header page, select Settings> Create Custom Header
Now this header page is separated from your global header settings, and you may add a banner ad or image widget underneath the existing navigation without affecting the other pages of your event!
Here's a demonstration of this process: