“Caylee’s death has gone un-avenged!” HLN star Nancy Grace shrieked in disbelief as the verdict was read in the Casey Anthony murder trial.

“Tot Mom will be walking free!” Grace grieved Tuesday afternoon as the Florida jury acquitted Anthony of murder, aggravated child abuse and aggravated manslaughter in the death of her 2-year-old daughter — though the jurors did find Anthony guilty of providing false info to the cops.

Five million people watched Grace as the verdict was read about 2:15 p.m. Tuesday — HLN’s best ratings performance in any hour in its history, according to Nielsen numbers issued Wednesday afternoon.

“The devil is dancing tonight!” Grace continued, hours after the verdict, on her prime-time show. About 3 million caught that performance — the “Nancy Grace” show’s biggest audience ever.

Other news outlets might have been equally stunned by the verdict: ABC News on Wednesday called it a “jaw-dropping not-guilty verdict” as it plugged its coming interview with Jennifer Ford, who said she and her fellow jurors cried and were “sick to our stomachs” after voting to acquit Casey Anthony of charges she killed Caylee but that they could not convict because “there was not enough evidence.”

This grisly murder trial has been the making of Grace — June had been her highest-rated month ever, with her prime-time show averaging 1.5 million viewers. And Tuesday, she emerged from the rubble having been crowned — by Web site Gawker and others — The New Queen of Grief Porn.

Grace was best at serving up to viewers what they wanted to hear. According to NM Incite — a Nielsen/McKinsey joint venture that provides social-media intelligence — 64 percent of people on Twitter disagreed with the verdict, and only 1 percent agreed; the other 35 percent were “neutral.”

“In the end, Tot Mom’s lies seemed to have worked,” a bereaved Grace lashed out after the verdict was revealed.

“Caylee, her 2-year-old little girl, found just 15 houses from where Tot Mom puts her head on the pillow every night; her body decomposed — nothing but a skeleton gnawed on by animals, disarranged there in a trash dump that used to serve as a pet cemetery. Little Caylee — thrown away like she was trash.

“And now, for the rest of our coverage, Caylee will be in our hearts, regardless of what this jury or anyone else does or says.”

Spitzer’s ‘Arena’ canceled

Eliot Spitzer’s “In the Arena” is out of business. CNN gave the Guv the hook so it could deploy Anderson Cooper to the 8 p.m. time slot, in the hopes he can gin up an audience for the network’s struggling 9 p.m. Larry King replacement show, “Piers Morgan Tonight.”

“AC360” will run again at 10 p.m. In late September, CNN will add a new show anchored by Erin Burnett — former co-anchor of CNBC’s ‘Squawk on the Street” and “Street Signs” — at 7 and 11 p.m. “John King USA” and “The Situation Room With Wolf Blitzer” will both be broadcast one hour earlier — at 6 p.m. and 4 p.m., respectively — than they now air.

At the epicenter of this whirlpool of scheduling moves, “Piers Morgan Tonight” will stay put at 9 p.m.

And so ends the cable news network’s attempt to bolster its prime-time ratings by dipping its parched tongue into the restorative waters of ideological-debate TV that has done so much for the ratings of rivals Fox News and MSNBC.

“Today we are announcing a new evening lineup that showcases our journalism, and further differentiates and distinguishes CNN,” CNN/U.S. chief Ken Jautz said Wednesday in a memo to staffers.

Back in June of ’10, CNN announced that Spitzer (the disgraced/rehabbed former governor and New York Democrat) would be joined by Pulitzer Prize-winning conservative columnist Kathleen Parker (a Washington Post columnist and member of The Washington Post Writers Group) for a new program called “Parker Spitzer.” That announcement was made by then-CNN President Jon Klein — who, ironically, was given the hook himself before the show actually debuted.

The show did poorly in the ratings. CNN cut bait on Parker in late February — because low ratings are always the chick’s fault in the news biz — and gave Spitzer his own show, called “In the Arena.” Which also fared poorly and which, on Wednesday, became Out of Time.

In his memo to staff Wednesday, Jautz said CNN is in discussions with Spitzer about an “alternative role.”

News flash: “I’m looking forward to the new time slot and am excited to share AC360 with a new audience at 8 p.m., while still connecting with my regular viewers at 10 p.m.,” Cooper said Wednesday in CNN’s announcement.

If Blitzer and King had anything to say about their time-slot changes, CNN did not feel they merited inclusion in the announcement.

Spader’s new ‘Office’

James Spader is joining NBC’s “The Office” as a series regular next season. He will continue to play salesman Robert California, having guest-starred on the show this season in that capacity, as the producers sought their Steve Carell replacement.

In the Thursday comedy series, California was hired over the summer as the new office manager, but he gets himself promoted to company chief executive within hours of his arrival.

(Kathy Bates, who had played Jo Bennett — the chief executive of the office’s parent company — over two seasons in a recurring role, left to star in NBC’s drama series “Harry’s Law.”)

“The Office’s” Season 8 premiere is scheduled for Sept. 22.