Washington ? The serious news of the day, from Saddam Hussein’s spider hole to Medicare to gay marriage, served as fodder for song, dance and silly dress-up Saturday night in the Gridiron dinner, a 119-year tradition of Washington journalism.

In the most unusual turn of this year’s satirical script, syndicated columnist Robert Novak, who sparked a federal investigation by printing the name of an undercover CIA officer, was taking the stage as that CIA officer’s disgruntled husband, former ambassador Joseph Wilson.

Dressed as Wilson in top hat and cutaway coat, Novak sings of himself: “Novak had a secret source … so he outed a girl spy the way princes of darkness do. … Now John Ashcroft asks Bob who and how, could be headed to the old hoosegow.”

A federal grand jury is probing whether someone in the Bush administration leaked the CIA officer’s identity, possibly a felony. Novak hasn’t commented on the investigation until the Gridiron.

Founded in 1885, the invitation-only Gridiron Club exists solely for its annual white-tie dinner, attended by Cabinet secretaries, congressional leaders and the like. The show has been visited by every president since Benjamin Harrison, except one — Grover Cleveland.

Bush spoke at the first three Gridirons of his term but skipped this year’s show in favor of a summit at his Texas ranch with Mexican President Vicente Fox.

Gridiron President Al Hunt, a columnist for The Wall Street Journal, spun that into a pun about conservatives’ fondness for Fox News Channel: “That pretty much sums up the White House philosophy: Why waste time with newspaper reporters when you can spend quality time with Fox?”

Vice President Dick Cheney agreed to take Bush’s place, appearing along with two New Yorkers considered possible contenders for the 2008 presidential race — Democratic Sen. Hillary Clinton and Republican former Mayor Rudy Giuliani.

Clinton took a good-natured jab at Giuliani, a potential adversary in some yet-to-be determined contest.

Alluding to the former New York City mayor’s old comb-over and his new emphasize-the-bald hairstyles, she noted that “in Washington the cover-up is always worse than the truth.”