Michael Nguyen spotted a post by Dave Winer that shows Google testing this weird expand and collapse Google search user interface. Basically, a search on Canada brought back little blue arrows on the left of the page title, when you clicked on the arrow, it displayed a picture, content from the site and a “search this site” box. For an image of it in action, see here.
Postscript: See also some nice screenshots on the feature from Yellowpipe here.