The New York Times printed a crossword with two possible answers

On Election Day 1996, one clue read "Lead story in tomorrow's newspaper." The squares could be filled with "CLINTON ELECTED" or "BOB DOLE ELECTED," and incredibly, either answer worked perfectly with the intersecting clues.

To emphasize how clever this was, this meant that not only did they have to take into account the one clue having to have the same number of letters, but also that all the intersecting clues had double meanings. For example, one read "Black Halloween Animal," which could be Bat or Cat, depending on which answer you picked. Check out the source for the full details.  

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