The main storyline running throughout Season 4 has Amy Poehler's Leslie Knoppe running for Pawnee City Council. Executive producer Michael Schur revealed at PaleyFest last night that they shot one version where Leslie wins, and another version where Leslie loses the election.
Michael Schur wouldn't reveal which version will air, but added that the decision to shoot both versions was, "in case we change our minds," and to throw outsiders, "off the scent." It is said the 200 extras gathered were told to start cheering during the scene where Leslie won, and were confused when the mood changed entirely as they filmed the same scene where she lost. Amy Poehler also added that the versions, "both ended the same way, thanking everyone for their hard work."
Michael Schur added that no one outside the production knows which version will air. After tomorrow night's Episode 4.18: Lucky (which features a guest-starring stint by Sean Hayes), Parks and Recreation will go on a brief hiatus until Thursday, April 19, due to Community's return to the Thursday night lineup.