For me at least, there's been a humongous increase in these adds that play voice clips telling you either your computer has been infected, or that they're going to delete your hard drive if you leave the page. I'm going to take some screen shots and update this post with each of them as I find them.
Most of them are not really a big problem since they go away once you change pages or refresh the page, though there's at least one that locks the page so you can't do anything until you close the page.
Edit 1: Here's a snip of the add that locks the page. When the add loads it plays a single electronic beep. After that anything you try and do won't work other than closing the page.
Edit 2: This add start playing a computerized voice that tells you there's a virus/spyware/malware on your computer and that you should call the number they list to be instructed on how to remove it. I didn't want to risk touching the add, so I didn't try searching for where the number was listed on it.
Edit 3: Sorry, I just realized I forgot to copy and link the url for each of those....
I will note though that simply by refreshing the page the add goes away. Maybe it'd be more useful if I copy the url for the adds
themselves? I'll try that by right clicking next time I come across one.