Geoff Pullum presents yet another wonderful ambiguous headline: "Leahy wants FBI to help corrupt Iraqi police force". We'll never be at a loss for such examples, given the nature of headlines.
So, as Geoff said, we don't really need to invent ambiguous sentences, like the celebrated We saw her duck, which he attributes to Jerry Sadock and me; you can find them all over. Just to keep the record straight, Jerry and I didn't invent that one; we took it, with attribution.
Second things first. We saw her duck comes from Zwicky & Sadock, "Ambiguity tests and how to fail them", in a 1972 Syntax and Semantics volume edited by John Kimball. In which we say that we got the example from Dennis Stampe (not linguist David Stampe, but his brother, philosopher Dennis Stampe).
By the way, sharp-eyed readers will have noted that there are more than two readings for this sentence, involving the present tense of the verb saw 'use a saw on' and/or the noun duck 'kind of cloth'.
The larger point is that it's almost impossible to write headlines without occasionally producing examples that are laughably ambiguous (or that induce garden-pathing). Two reasons for this: headlines lack many indicators of structure (and hence interpretation), which have been suppressed for brevity; and they come at the top of the story, where they have no linguistic context (and, often, you need a lot of cultural context as well). I once spent some time writing newspaper headlines, and it was a hell of a task (though interestingly challenging).
Of course, we here at LLP, LLP, are as prone as anyone to enjoy the headlines that run awry -- ambiguous, garden-pathic, or just puzzling headlines. Here are a few from my collection that I don't think I've posted about here. (Sources on request.)
Truck leads police to molest suspect
City ducks vote on transportation fee
Horse attacks trigger debate
Warnings on river, lake fish jump
Associate of Black savages report,
as media feeds on tycoon's fall
DNA leads police
to rape suspect
Mammoth Remains Unearthed
China Cabinet Orders a Drive Against Inflation
Reading X-Rays In Asbestos Suits Enriched Doctor