If you’re into media ethics history — or just 
like to see power-chord journalism with a slice of ethical quandries — then take a look at The Chicago Sun-Times online publication of The Mirage series.
In 1977, The Chicago Sun-Times went undercover with the non-profit Better Government Administration and CBS to show rampant corruption among public officials who regulate businesses. Their bar, aptly named “The Mirage,” was chock-full of cameras and other equipment that allowed reporters to surreptitiously capture the full-on glory of graft, bribes and threats.
The series, published in 1978 and later as a book, led to lots of convictions and calls for reform — and a fight over the ethics of deception that continues to rage. Pulitzer judges in the general reporting category gave the series its nod for a win, but Washington Post editor (and Pulitzer board member) Ben Bradlee persuaded others that such deception was not award-worthy.
Since then, there are plenty of examples of deception and undercover work by journalists. But none seems to have received the attention drawn by that bar.