Dolly Parton singing "Jolene", but pitch changed sounds JUST like a guy singing it "I beg you Jolene, please don't take my man...".
That was funny, but I tried Gotye "Somebody that I used to know". It's better than the original, with a very nice female voice!!!

Just play it in Apple Quicktime, open the A/V controls, and slide the pitch to the right (best if not QUITE full right).
Of course, if you want a deeper voice, slide left.
Also tried Kenny Rogers Coward of the County... pretty durned funny too.