Problem background ad just with CNN page. Help?

When I go to www.cnn.com with Safari a moment after the page loads a Dish add fills the background (all around the edges and sides of the page) and then although I can see the CNN news posts nothing on that page responds. I have to (and can) back out of the page (after clicking a couple times). Everything else on Safari seems to be working fine, and I can even go to the CNN international edition and it works fine. But whenever I go to the straight up www.cnn.com page I get this other thing. I tried clearing today's history, cookies and website data (the problem is only a few hours old) but that didn't help. Nor did restarting the computer.

Ideas?