Google has been testing various flavors of what Danny Sullivan calls, "Middle of Page Google Refinement" results. Danny just wrote about it at the SEW Blog here. You can see these results for random searches, one such search that currently works is relentless and if you don't see it, here is a picture of it. For some images of older tests, take a look at "Alternative Searches" and then a more mature version named "Dissatisfied?" Now it seems to be "See results for: [new keyword phrase here]".
Anyway, Danny Sullivan split off GoogleGuy's post from yesterday into its own thread, named Google Confirms Middle Of The Page Query Refinement No Longer A Test; Suggest A Name! It is legit, this is no longer in "test mode" and is out in the public. But sadly, there is no official name for this feature. Danny prefers the name "MidBox Results", I tend to like "Alternative Searches" if that is what it remains to be. If they start putting forms of "Smart Answers" in the box, then "MidBox Results" seems perfect, but if it is purely organic, then I think "Alternative Searches" are the way to go. Why? Because OneBox, to me, seems less purely organic to me than does the refinements we are shown here.
Forum discussion at Search Engine Watch Forums.