Oh sure -- it's easy for Howdy Doody. He's made of wood. He's been able to remain 6 for 40 years. He can still get away with exclaiming things like "Ho-ho, wowee-boy!" The rest of us have been expected to mature.

Somehow it is reassuring, if in a goofy way, to find that Howdy is much as we left him (or did he leave us?) on "It's Howdy Doody Time: A 40-Year Celebration," the syndicated two-hour slapstick commemorative Channel 5 airs at 8 tonight. Buffalo Bob Smith is older, grayer, and there's more of him, but he's still as backslappingly congenial as a garrulous uncle. When he tells you you're having fun, you may find yourself still believing him.

For 13 years on NBC, from 1947 to 1960, "Howdy Doody" was an insistent television ritual, a relatively raucous puppet show that featured, in addition to Howdy, marionettes like Dilly Dally, Flub-a-Dub (eight animals in one) and Mister Bluster, corrupt mayor of Doodyville. "Howdy Doody" educated us about, among other things, the fallibility of politicians.

Smith, who hosts the special, helped create the series and supplied Doody's voice, staying carefully out of the shot while Howdy was talking (until the show's later years, when the voice was prerecorded). He welcomes back such flesh-and-blood regulars as Clarabell the seltzer-spritzing clown, now played by Lew Anderson, and Chief Thunderthud, the "Cowabunga" Indian from the Ooragnak tribe, still played by Bill LeCornec.

Judy Tyler, who portrayed Princess Summer-Fall-Winter-Spring, is "no longer with us," Smith confides, so a new actress assumes the role. The special includes clips from the original show and, as a major annoyance, a flock of guest stars who drop by to sit in the Peanut Gallery or send their greetings on tape.

The program reaches an excruciating low point when Howdy, who thinks everyone's forgotten his anniversary, sings plaintively, "It's hard to find a girl for a guy like me" and wonders, "Am I made of the right stuff?" He sings that he hopes he'll lose his virginity "before I die." Die? What's he worried about, Dutch elm disease?

"Celebration" will be endured by those who remember the earlier show just because it makes such an antic raid on the old memory bank and evokes past innocence. Characters one may have forgotten, like Capt. Windy Scuttlebutt, invade one's consciousness anew, and songs like "Cross the Street With Your Eyes" sound eerily familiar.

In those "Howdy Doody" days, parents worried about their kids crossing the street. Now they worry about them being assailed by child abusers and drug pushers.

Among the guests who have no real business being there are Johnny Carson, Jerry Mathers ("The Beaver," but fat as a bear), Gary Coleman, Pee-wee Herman (clearly running out of material, and that may be just as well), and the quintessentially insufferable Gary Collins, interrupting host of "Hour Magazine."

Milton Berle, who was "Mr. Television" during a time when a title like that was actually considered an honor, wanders through and greets Doody, and at least this rendezvous of icons has some cultural resonance. The rest of it is just hypey gush.

The clips are really what keep you watching -- the clips and Smith's peerless ebullience. He will not take "Oh shut up" for an answer, and the bonhomie, however forced, has a charm. He's like the counselor at camp who would not let you sleep late, insisting on rousting you for games, songs and general romping.

It does seem an overstatement for the announcer to describe him as "the man every little boy idolized and every little girl wanted to marry." But of all the surrogate parents TV provided in the '50s -- people like Jimmie Dodd of "The Mickey Mouse Club" or Frances Horwich of "Ding Dong School" -- Buffalo Bob always seemed the best sport. He was laughed with as often as laughed at.

Near the end of the show, he addresses those watching who were there at the beginning. "And you know, as you peanuts grew up," he says, "you stood up for what you believed in." That's right. In the '60s they stood up against the Vietnam war. And in the '80s, they stand up for retaining the mortgage deduction on their income tax.

A little tacky, a little too long, and often funny only because it's so dumb, the special still has appealing homecoming qualities. When the Peanut Gallery is promised "ice cream and cake," little bells may go off in your head. Ice cream and cake -- those magical words! They rank right up there with "Hey kids, what time is it?" For a couple generations of '50s kids, "Howdy Doody" was ice cream and cake, every afternoon. Ho-ho, wowee-boy.

'Celebrating Gershwin'

Part 1 of the PBS "Celebrating Gershwin" special, last week, was terribly good. Part 2, tonight, is simply grand. " 'S Wonderful," which recalls George Gershwin's Hollywood years, airs at 9 on Channel 26 and will be simulcast on WETA-FM (90.9).

This is the show that includes Bob Dylan mangling the Gershwin tune "Soon" and Christopher Walken getting lost in "They Can't Take That Away From Me." Much more notably, Cynthia Haymon and Ruby Hinds share a shimmering duet from "Porgy and Bess" that was deleted from the final version of the opera and a ballet to Gershwin tunes danced by Mikhail Baryshnikov.

Gershwin's neglected "Second Rhapsody" is performed, with host Michael Tilson Thomas conducting, and the rare home movies include color footage of George and Ira at play, and of Fred Astaire on the set of "Shall We Dance." Liza Minnelli and Michael Feinstein duet, as do Tommy Tune and Drew Barrymore, supremely cute together.

'S awful nice, all of it. But 's paradise when John Green, the composer and conductor, appears near the conclusion to lead the band and soloists (including Rosemary Clooney and Maureen McGovern) in some of his vintage arrangements of Gershwin songs. It is almost impossible to imagine these lively classics sounding better or fresher.

Green, who knew both Gershwins and later was head of the MGM music department, is in happy, hammy form. On Oct. 12, months after the performance was taped, he suffered a stroke while en route to Nashville. But a spokesman said yesterday from his home in Beverly Hills that he is "recovering by leaps and bounds" and is expected to leave Cedars Sinai Hospital next week.

There aren't enough bouquets in the world for him, nor for the producers and performers who took part in the "Celebrating Gershwin" specials. Bobby Short has the final words, from the last Gershwin song, "Our Love Is Here to Stay," with Green at the piano. Our Gershwin is here to stay as well.