“Reality TV is the reality of TV,” says Valerie Cherish, the fictional star of “The Comeback,” which is the made-up title of the pseudo reality TV show set in the world of “Room and Bored,” a nonexistent sitcom on a fabricated network, all of which takes place on HBO, which isn’t even television at all. If that doesn’t make sense to you, don’t worry – it’s not supposed to. “The Comeback,” the new Lisa Kudrow comedy series that debuts this Sunday night at 9:30 p.m. on HBO, appears to have been written as an inside joke among a group of friends to which you don’t belong. But the good news is you wouldn’t want to know them, anyway.

The saddest news of 2005 so far, for fans of great television, is that “The Comeback” doesn’t even come close to greatness; instead, it’s a painful exercise in self-indulgence that will make most intelligent viewers cringe. The premise – that a fading sitcom star allows television cameras to follow her return to series television in a role reminiscent of Mr. Roper on “Three’s Company” – is nothing less than nauseating, and its execution is at times deliberately so. This is a show that actually expects viewers to laugh at the sound of one of its central characters defecating, off-screen – the kind of joke I associate with 11-year-olds who think it’s funny to fart. Which is funny – when you’re 11.

We’re supposed to believe that the network that plans to launch “Room and Bored” has insisted that Valerie Cherish (even her name is painfully stupid) agree to this reality show as part of her deal – a fairly unlikely scenario given the grim portrayal of the network in virtually every scene. Early in the first episode, we see Cherish go to the network for what she thinks is a rubber-stamp casting session, only to discover that Marilu Henner and Kim Fields (inexplicably playing themselves on this uneven playing field of reality) have also been called in to audition. I couldn’t help wishing that Ms. Henner or Ms. Fields would get the part and put us all out of our misery. The fictional Cherish gets the job, only to discover that it’s not the lead role she’d been led to believe it was, but a supporting role to a group of giggling hotties who share a California beachfront house.

Wait, it gets worse. And worse. And worse.

The supporting players of “The Comeback” have all the diversity and substance of a bad network sitcom from the 1970s.They include a flamboyantly gay hairstylist (now there’s a fresh concept) whose idea of banter is to count his melanomas, and two angry, dysfunctional comedy writers who do nothing but scowl. Every so often, a real person shows up to further muddle the formula. James Burrows, the legendary television comedy director (“Cheers,” “Taxi”) who’s famous for his speedy shooting schedule, shows up as the director of “Room and Bored” to heap yet more psychological abuse on Cherish; in the first two episodes of “The Comeback” made available to critics, her ego gets so shattered that it’s hard to imagine her surviving the summer. The endless cruelty toward Valerie Cherish makes you yearn for those heartwarming winter nights when Kirstie Alley sparred her way through six episodes of “Fat Actress,” redeeming herself with her wit. “The Comeback” even repeats the essence of a joke from “Fat Actress” about the People’s Choice Awards – and Ms. Alley told it way better.

It’s sad to see Michael Patrick King, who supervised the evolution of “Sex and the City” from a smart, hip concept into a television classic, behind the wheel of this broken-down star vehicle. And make no mistake: That’s what it is, despite all the trappings of high-concept sophistication. The show got its HBO green-light and Sunday night time slot thanks to the very phenomenon that “The Comeback” tries to ridicule – the painful addiction television executives have to shows with famous stars of former sitcoms attached. Coming off nine years on television’s biggest hit series, Lisa Kudrow could have done any show she wanted and not endured any of the indignities with which she afflicts her alter ego, Valerie Cherish. We’re supposed to respect her daring decision to take the “creative” path here, but it’s hard to admire her wanton assault on the industry that earned her so many millions.

Others will criticize “The Comeback” for being excessively inside; I didn’t object to that, at least in theory. HBO has become something of a specialty act for writers who want to explore the dark side of Hollywood, with wonderful shows like “The Larry Sanders Show” and, more recently, the underrated George Clooney series, “Unscripted.” But for “The Comeback” (and, implicitly, HBO) to position itself as morally superior to the networks, and to be mercilessly condescending about reality television – and comedy – is, I think, morally indefensible. After all, “The Comeback” intends to be a little of both; the trouble is, it succeeds at neither.

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“Into the West” update:

I’m pleased to report that I have made through the midway point of the first two-hour episode, and have only fallen asleep twice. Eleven more hours … wish me luck!