Google has in the past year or so introduced graphical banner ads in addition to textual ads, which can be allowed or disallowed at the discretion of the AdSense account owner. In our case, since we're sharing a server with GameWarden that MatthewPapa is paying for (and since my AdSense account was disabled on account of invalid clicks), these ads are from MP's AdSense account, and however he chooses to define them is what we get.
Now personally, I'm fine with static or gently changing images as banner ads. It's the spasticly blinky flashy ones that I hate. So, if those start showing up, or if lots of people really hate any kind of graphical banners, let me know, and I'll work with MP to limit the ads to textual ads only.