The thought of reliving the Iranian hostage crisis may be about as repellent as a thought can get, and yet tonight's PBS "Frontline" documentary, "Hostage in Iran," turns what was an infuriating and humiliating ordeal into a riveting emotional thriller. The 90-minute report, at 9 on Channel 26 and on the Maryland Public Television stations, follows the crisis chronologically from before the beginning ("Day Minus 14," the narrator says) to the end.

Many of those who were hostages are interviewed by unseen reporters, and their reminiscences are strung together with news footage of the crisis so it can be followed more or less step by step. Where the filmmakers erred is in slighting the human aspects of the story so as to replay the politics. Viewers may find they want to hear much more about the peculiar psychological stresses of imprisonment and isolation than they do about the shah, the negotiations and the Ayatollah Khomeini.

For instance, Marine Sgt. James M. Lopez, who is the most frank of all those interviewed, remembers that a couple of people "cracked" under the strain and "went slightly crazy," including one male hostage who occasionally ran about the room ranting. There were at least two suicide attempts, it is stated. And there is a black-comic note: One of the Iranian guards told his prisoners after months of incarceration that he was under such great pressure from his job that he risked a nervous breakdown.

Some of the hostages raised eyebrows here when, during the siege, they made statements, captured for television, that seemed excessively pro-Iranian and anti-U.S. policy, even considering the fact that the statements were made under obvious duress. But that unpleasantness is never revived here, even though it might be illuminating to hear how those hostages feel about it now.

As the documentary begins, it appears the chronological preoccupation of the filmmakers is going to weigh it down. There are some pretentious production touches, like fades to black after "Day 2," "Day 3," "Day 267" and so on. And there is a tendency to throw in dubiously authentic visual asides during the hostages' recollections. If a man says he was confronted by a mob in the street, we see a quick shot of a mob in a street, although it isn't likely that it's the mob in the street that confronted this particular man.

Sometimes these intrusions are probably inserted just to cover edits in hostage remarks. But some are unnecessarily disruptive, and they suggest the filmmakers didn't trust the hostages' descriptions to be compelling enough. They are compelling enough.

"Hostage in Iran" traffics in negative nostalgia. Old faces, old strange-sounding names, come back as if from the very distant past. How long is a media generation? Perhaps as long as it takes for new bad news to supplant old bad news. The Iranian hostage crisis now seems to have occurred eons ago, and shots of Jimmy Carter as president have an unreal, maybe even an unearthly, cast.

We are reminded again how badly the British behaved at the beginning of the crisis -- ejecting from their embassy five Americans who had escaped from the terrorists -- and how grandly Canada came to the rescue, helping to smuggle Americans who remained free out of the country with false Canadian passports provided by the CIA ("Hostage" was produced and directed by a Canadian, Les Harris). A Thai cook was "an unsung hero" of the crisis, according to the narrator; he risked his life to protect the Americans before they fled to safety.

There are grim ironies: Carter impotently imposed "economic sanctions" as a way of chastising the Iranians much as Ronald Reagan, supposedly the bane of world terrorism, would do later against Qaddafi and Libya. Perhaps the Iranian crisis should be thought of as the beginning of the new Terrorist Age. We were shocked by it at first; later it became practically a way of life. It became a nightly ABC News show with Ted Koppel. Perhaps by the year 2000 we all have been so numbed by terrorism that we will be shockingly unshockable.

As did the crisis, the documentary ends with homecomings, scenes that still wield a tremendously moving clout. Before they were set free, the hostages on occasion got to send messages home via television, and in the most poignant of these, during the hostages' second Christmas in captivity, Kathryn L. Koob, then director of the Iran-American Society in Tehran, not only speaks but sings. She sings a child's Christmas carol, "Away in a Manger," which ends with an entreaty to "the Lord Jesus": "Take us to Heaven, to live with Thee there."

As the hostages clung to shreds of hope, those of us who watched on television clung to little moments of sanity within a mad context. In the age of terrorism and global television, sanity has perhaps become a thing that exists only for little moments at a time. The mad contexts usually obscure it. 'The Muppets'

Lobsters escape from their pot and run from the kitchen with bandido guns blazing. A Coozbanian mating ritual ends with the two participants exploding in a great blam. Chickens peck out a ditty on a piano, animals in the forest sing an old Buffalo Springfield tune as a protest song, and a frog guest-hosts for Johnny Carson on "The Tonight Show."

What could this be but the world of the Muppets? Three absurdly jolly decades of Muppetistic mirth fly by tonight on a CBS retrospective, "The Muppets: A Celebration of 30 Years," at 8 on Channel 9. All heck breaks loose from the opening sequence and things go alternately pell-mell and helter-skelter from there. In short, another manic Muppety romp designed, as ringmasters used to say, for children of all ages -- from moppets to yuppets and their grannies and grampses, too.

Set at a rowdy banquet that nicely mimics innumerable awards shows and celebrity testimonials to other celebrities, "Celebration" traces the origin of the Muppets back, via clips, to their Wilkins Coffee commercial days in Washington, on through the Ed Sullivan and Jack Paar show appearances (where a character that later became Kermit the Frog wears a bizarre blond wig) and then explosion by explosion into the present.

Today the Muppets are a giant thriving capitalist empire, except that in such work as the PBS "Sesame Street" and HBO's "Fraggle Rock," the essential whimsical integrity of the troupe survives. Jim Henson, who started it all, shows up in a brief cameo near the end of the program; a Muppet waiter hands him the check for the banquet. This is not long after Miss Piggy and Kermit have reprised their famous roles in "Casablanca" and Fozzie Bear has exclaimed to Kermie, "Oh, frog of my heart!" To which Kermit responds, "Let's not get mushy."

Andrew Solt produced the special, and very well, too. Guest stars seen in clips from "The Muppet Show" or the Muppet films include Orson Welles, Zero Mostel and Ethel Merman. Although Kermit's "It's Not Easy Being Green" is clearly a self-pity ditty, it comes cheerfully alive when Kermit sings it in duet with Ray Charles. The Muppets bring everybody down to their level. That's the beauty of it.