NEW YORK — The Super Tuesday presidential primaries this week top off an unexpectedly thrilling and profitable month for television news with a super mystery.

One day, primaries in nearly half of the states and two contested races — it has never happened before, certainly not on this scale. November election nights are massive undertakings, but networks generally know from experience what to plan for.

This time, not so much.

While a headache for news executives, the people who cover politics for a living can't contain their glee.

"This is just such a hell of a story," said CBS News "Face The Nation" host Bob Schieffer, happy he put off retirement to be a part of it.

News execs figured it would be an exciting political year. But they have made adjustments on the fly to capitalise on the intense public interest early on.

Nowhere will that be more evident than on Tuesday. All three broadcast networks long ago set aside an hour for a Super Tuesday wrap-up, but ABC decided to give its entire prime-time to the story. CBS News doubled its commitment to two hours.

An ABC News-Washington Post poll taken last week found Americans nearly as excited about Super Tuesday (37 percent) as they were about the Super Bowl (40 percent). College graduates were more excited about the political contest, 53 to 33 percent.

CBS News' Jeff Greenfield dubbed 2000 the "Seinfeld election" because, until its bizarre finish, it seemed essentially about nothing. Remember when people said there really wasn't much difference between Al Gore and George W. Bush?

"You don't hear that anymore because there's big stuff at stake," he said.

Arguably, more important issues will face the next president than at any time since he's been voting, said ABC News President David Westin, 55.

CNN's prime-time weeknight viewership in January leaped 39 percent from January 2007, according to Nielsen Media Research. Both CNN and MSNBC, which was up 33 percent, have aggressively promoted their political teams. Fox News Channel's viewership was essentially flat, up four percent.

"We're pleasantly surprised by the level of interest," said Jon Klein, CNN US president. "We knew they'd be interested. We didn't know they'd be obsessed. We're obsessed, too, so that's a good match."

Looking for a way to compete against college football games on New Year's Day, CNN created its "Ballot Bowl." The non-stop political coverage emphasized the candidates' own words, either in stump speeches or news conferences. Klein believes viewers are attracted to CNN's "aggressively independent" coverage.

The "Ballot Bowl" was such a hit that CNN continued it over January weekends and, last week, substituted it for the international newscast it normally runs weekdays at noon.

Between the motormouthed Chris Matthews and provocative Keith Olbermann, MSNBC has tried to make its coverage vibrant, said NBC News executive Phil Griffin. Joe Scarborough's "Morning Joe" programme, the network's replacement for Don Imus, has become a political showcase.

Fox gave anchor Shepard Smith a two-hour political special within its Super Bowl preamble, while being careful not to upset football fans. It was scheduled to end more than six hours before kickoff.

ABC News sensed the political interest early, when its January 5 pair of prime-time debates had nearly twice the audience of what the network usually airs on Saturday. ABC was the only broadcaster to set aside 30 minutes in prime-time for New Hampshire primary coverage.

About two weeks ago, Westin approached the network's West Coast executives with a request for more Super Tuesday time. They decided on a remarkable — for this era — five hours of coverage that lasts until 1 a.m. on the East Coast.

"I am genuinely proud of the network and the company for stepping forward this way," he said. "I think it's the right call and the right thing to do."

It also gives anchor Charles Gibson a competitive opportunity against his close NBC News rival Brian Williams. Choosing not to miss out on potential revenue, NBC has scheduled a two-hour "The Biggest Loser" and is keeping politics largely confined to cable.

New options Tuesday include a six-hour online video report featuring journalists from the Washington Post and Newsweek available through those publications' websites. BBC America televises five hours of coverage that will also be seen worldwide. Ted Koppel is joining the BBC's team to offer analysis, but not until Wednesday night.

The challenge facing news organisations Tuesday is seeing how trends develop, or even if they do, with so many states involved. The delegate count is ultimately more important than the popular vote and, particularly with the Democrats, may take a painstaking effort to sort out.

"It's going to be wild in the control room that night as exit polling comes in, as results come in and we try to figure out what it all means," said NBC's Griffin. "You can plan all you want. We don't decide what the narrative of the night is."

Many news organisations expect to be staffed as fully Tuesday as they will be November 4.

"It's a good challenge to have," Westin said. "This is a wonderful story."