It's hard to find something compelling to do with a classified page. Lines and lines of monotonous type with the occasional header don't exactly afford creative freedom. But Felipe Salazar has shown (on Behance) that Cocinas Corona used the look of a classified page to make a unique full-page ad.
The ad looks like a typical classified page, but skews columns such that the paper becomes a sort of magic eye image of a kitchen. Check it out for yourself:
The text translates to "the kitchen you're imagining is HiperCentro CORONA."
You can see other images of this ad at Felipe Salazar's Behance here.