"If you don't vote, you can't complain," the old saying goes. But that's not a great foundation for an ad campaign about voting—it's the wrong way around. How about: "If you do vote, you can complain." That's more like it. Ad agency Third Street latches on to Americans' time-honored propensity to bitch endlessly about anything and everything in a new campaign called Real Complainers Vote—a nonpartisan initiative to get young people engaged in the political process.