Google May Be Pushing Out A New Update: Possibly Penguin?

I am seeing very early signs of another possible Google update both based on chatter at the WebmasterWorld and in other forums and social media spaces. I am also getting private data shared with me by those who are tracking this closely.
Update: Google tells me this is not Penguin or any spam quality control change.
The feeling is that Google is testing a new Penguin refresh and that it may be rolling out slowly. Or that it might be something else. So you know, we had a Panda 4.0 update last week, and then last weekend (before Panda 4) we had a Spam algorithm update. Prior to that we reported on tons of ranking shifts which Google denied despite all the signs of an update.
And now, we are seeing something rolling out yesterday, that had big impacts on some sites.
Here are two graphs of sites impacted by a few things, including Penguin and notice the spikes in both over the past couple days:

On the 26th, these sites, both without any manual actions, saw huge changes. This was well after the official Google updates.
Last night, Rae Hoffman posted on Twitter that she has seen something going on..