It’s difficult to imagine a show more specifically targeted at theater insiders than Gerard Alessandrini’s long running “Forbidden Broadway.” As the revue enters its 22nd year, that’s precisely the problem: Every regular theatergoer – anyone, for that matter, who arrives in the Theater District by any means other than tour bus – knows better than to see an old, tired warhorse in its fourth or fifth season, let alone its 22nd.

Mr. Alessandrini knows this, too, the latest incarnation of his affectionate, irreverent tribute to the Great White Way, “Forbidden Broadway: Special Victims Unit,” confronts its age head-on, providing an hour and a half of always amusing, occasionally side-splitting fun that only rarely shows signs of doddering.

The lights come up on an older, wiser Annie Warbucks, that once-plucky girl with the curly red hair and the white-trimmed red dress. When last we saw her, snagging her Daddy for the last time on the stage of the then-Uris Theater, it was January 1983, one year after the first “Forbidden Broadway” debuted. The two icons are grown up now, but Annie’s far worse for wear.

“I’m 30 years old / Tomorrow,” she sings, still identically coiffed and clad but now world-weary and bored. Cigarette in hand, arms moving robotically through their choreographed paces, this Annie is a witty acknowledgement that what was fresh and wide-eyed in the early 1980s could over two decades easily become a pale shadow of its former self.

But then she’s suddenly gunned down in a hail of bullets. The “Law & Order” detectives arrive, introducing the audience to this “SVU” incarnation of “Forbidden Broadway.” It’s the perfect reference: a long-running franchise – and a deeply Broadway-entwined franchise – that has kept itself new through changes of cast and an always-new real world to play off of.

Like “Law & Order,” this “Forbidden Broadway” works fantastically well when it’s ripped from the most current headlines. “Come on along and listen to / the lullaby of Bombay,” the four-person cast sings in a spoof of this year’s Lloyd Webber debacle, “Bombay Dreams.” They’re easy jokes, yes, but they work.

“A fiddler with no Jew / Sounds crazy, no?” asks an anglicized Tevye, with Union Jacks as tztizit. (The lengthy “Fiddler” segment also considers the forthcoming replacement of the goy, Alfred Molina, by the faygeleh, Harvey Fierstein. “If I were a straight man,” Tevye sings, wearing his beard and shtetl cap along with Edna Turnblad’s seemingly Pucci-designed circus tent of a dress.)

An extended riff on the last Tony Awards is excellent, from its dead-on I’m-playing-to-the-gays-but-look-really-there’s-my-wife Hugh Jackman, thrusting and prancing in an open shirt and body-hugging gold lame pants, to a spectacular Carol Channing send-up.

But there’s no way this show can pack the punch it did in 1982, and the numbers that punch least are those least up-to-date. “Beauty’s Been Decreased,” about staffing cutbacks and the Disney show that’s run for more than a decade, is tough to care about. And the bit in which a falling chandelier hits the Phantom in the head was much funnier during the first Bush administration. Even a superb channeling of Bernadette Peters’s little girl-meets-brassy-belter voice and manner loses its edge when you remember “Gypsy” has been closed since May.

But “Forbidden Broadway” isn’t designed to be a groundbreaking night of cutting-edge theater. It’s supposed to be lighthearted, knowing fun. It is. The cast of four (including Megan Lewis, who was substituting for an ailing Christine Pedi) ably handles both the comedy and songs. Alvin Colt’s costumes carry just the right touch of mocking tribute, as does the choreography – especially in the “Movin’ Out” number (“Got a call from a weird lady / Calls herself Twyla”). Only the sound system is subpar, rendering Mr. Alessandrini’s virtuoso lyrics occasionally unintelligible.

In the last two decades, the opening number suggested, Annie’s had a hard knock life. For “Forbidden Broadway,” it’s been easy street.

(432 W. 42nd Street, 212-239-6200).