FRINGE. 9 tonight, Channel 29.

TWO OF J.J. Abrams' worlds collide tonight as Leonard Nimoy guest-stars on Fox's "Fringe."

Nimoy, who agreed to reassume Spock's pointy ears for the new "Star Trek" movie Abrams directed, makes his "Fringe" debut in the season finale, where he'll play one of the show's most-talked-about characters, Massive Dynamics founder William Bell.

"I called him and I just essentially started begging," Abrams, who co-created the Fox sci-drama, told reporters in a conference call late last week.

Nimoy seemed to be aware of the show, "but I don't think he'd seen it," Abrams said, adding that he "explained that there was a critical character who had been mentioned throughout the first season, and it was a big deal for the show."

Nimoy "was open to the idea, but he wanted of course to see the show," so they sent him some episodes, "and I was thrilled when he called back and said he thought it was intriguing and interesting," Abrams said.

"And that was how we actually ended up getting him to return to the role of Spock in 'Star Trek,' where we told him the idea, pitched him the thing, and his response was, you know, interested intrigue."

Nimoy's character, for those who haven't been following every twist and turn of "Fringe," which has already been renewed for next season, began his career as the lab partner of Dr. Walter Bishop (John Noble), the literally mad scientist whose work in "fringe science" lies at the show's core.

At some point, the two presumably parted company, one ending up in a mental asylum for 17 years, the other as the head of a vast conglomerate with deep pockets and even deeper secrets.

Though there's plenty of darkness in "Fringe," which stars Anna Torv as an FBI agent out to expose some of those secrets, it's the growing relationship between the often-befuddled Walter and his son Peter (Joshua Jackson) that's been the high point of Season 1, lending "Fringe" both a sweetness and a sense of humor.

Funny was always meant to be part of the mix, according to Abrams, who said one of the things he loves about the show "is the inherent humor and the insanity of it."

If "Fringe" takes itself too seriously, then "people will laugh at it," he said. "But if the show has humor inside of it, then the show itself is embracing and sort of admitting to the, you know, preposterous nature of many of the episodes. I love preposterous stories."

Preposterous, though, isn't as easy as it looks. Not with science moving so fast.

" 'Fringe' was never intended as a course on any kind of physics or medicine or science. It was always meant to be kind of a fun, cool and insane representation of what it feels like to live in a world where science is limitless in what it can do," Abrams said.

But no matter how far-fetched one of those stories might be, "invariably, there'll be a story, online, that you will see that is weirder than what you're writing, that really happened," he said.

"I think we all live in a moment where nothing surprises us anymore, where almost anything we would see online or in a paper, we would believe, unless someone whispered in my ear and said . . . 'That's b-------,' " he said.

More on Madoff

"I don't know. How do I know? How do [you] split an atom? I know that you can split them, I don't know how you do it. How does an airplane fly? I don't ask."

That's Michael Bienes, a certified public accountant and former unlicensed investment adviser who helped funnel hundreds of millions of his clients' money to pyramid-schemer Bernard Madoff, talking to PBS' "Frontline" (9 tonight, Channel 12) about what he'd understood - or not understood - about how Madoff got the returns he did.

And though there's little in "Frontline's" "The Madoff Affair" that should surprise any of us by now, it's astonishing how many of the other people who did business with Madoff, including people one would assume knew more about finance than Bienes knew about splitting atoms, betrayed similar ignorance.

If you're still trying to figure out why Madoff did what he did, you won't find any answers in "The Madoff Affair."

But the ignorance and indifference that made it possible?

It's all there. *

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