Google is testing an ad format, that I think is new, where it has three images in the ad, all that link to different landing pages. So if you click on one image, it takes you to one unique URL, if you click on a different image in the ad, it takes you to a different unique URL.

Here is a screenshot I took from a videocast made by Saad AK on Twitter:

You can see in the video, that I embedded below, that the ad clicks take you to different URLs:

I think this is new, but I can be wrong.

Forum discussion at Twitter.