"The Grudge." "War of the Worlds." "Saw." "The Village." "Brokeback Mountain." "Million Dollar Baby." Take a long look at that list, because out of all the hundreds of films ripe for spoofing, these six are the only ones even remotely referenced in "Scary Movie 4." A hugely popular slapstick series that will continue to be sequelized as long as horror movies (and, apparently, boxing dramas and same-sex romances) are made, this fourth effort is also by far the weakest. In fact, little effort seems to have been made at all. Director David Zucker (2003's "Scary Movie 3"), the granddaddy of the spoof genre who at his height of creativity made such classics as 1980's "Airplane!" and 1988's "The Naked Gun," has finally made a film on the level of those by his inferior imitators. "Scary Movie 4" is inconsistently funny, lazy, tedious, glaringly uneven, and ultimately may leave even die-hard fans of its predecessors feeling disappointed.

Making a fourth return to the role of sweet, klutzy dim-bulb Cindy Campbell is the ever wide-eyed Anna Faris (2005's "Just Friends"), by now a deadpan master of the spoof format. Faris has always been the plucky and reliable anchor of the insanity surrounding her in the series, but even something seems to be off with her. Likely no fault of the actress as much as it is of writers Craig Mazin and Jim Abrahams, Cindy remains the lead character and yet has next to nothing to do and isn't nearly as inviting and likable as usual.

The same most definitely could be said for Regina Hall (2005's "King's Ransom"), the only other consistent cast member of the franchise as Cindy's tell-it-like-it-is, often ill-fated best friend Brenda Meeks. Hall has inarguably been the standout performer ever since the 2000 original, and so it is especially painful to realize that (1) Brenda has infinitely less juicy material to work with despite being given more screen time than she had in "Scary Movie 3," and (2) Hall rarely captures the spirit of her great role. Soft-spoken when she should be rambunctious, sex-crazed when she should be more innocently sassy, this isn't at all the Brenda that "Scary Movie" devotees have come to love.

The plot this time is very well-constructed, smoothly interweaving the plots, character archetypes and uncanny set designs of "The Grudge," "Saw," "War of the Worlds," and "The Village." Unfortunately, the spoofs of said movies along the way are limp and uninspired, going way too often for predictable sex and bathroom jokes that aren't even clever as far as sex and bathroom humor go. When Cindy Campbell (Anna Faris) takes on her first assignment as a care worker for a catatonic elderly lady (Cloris Leachman), she immediately senses that something isn't right in the house. It turns out the place is haunted by the ghost of a child who passes along a curse to anyone who enters. Just as Cindy and new next-door neighbor Tom Ryan (Craig Bierko) spark a romance, they are split up as a TriPod alien invasion breaks out. As Tom and his estranged children Rachel (Conchita Campbell) and Robbie (Beau Mirchoff) head off to find safety, Cindy is reunited with old pal Brenda (Regina Hall) as they set out to find the one man (Bill Pullman) who may hold the answers to stopping the ghost child's curse. Their journey eventually leads them to a village straight out of the 19th-century, its residents terrified by the creatures said to roam the surrounding forest.

"Scary Movie 4" is full of wasted potential—where are the obvious references to such recent genre pictures as "Ring Two," "Red Eye," "The Exorcism of Emily Rose," "When a Stranger Calls" and "House of Wax"?—a fact that only becomes clear once the second half gets underway. The opening forty-five minutes have a few low points, especially the pre-title sequence starring Shaquille O'Neal and Dr. Phil in a parody of "Saw" that falls so flat it deserves to be watched alongside the absolutely hilarious "Exorcist" opening from 2001's "Scary Movie 2" for a comparison between smart and hair-brained slapstick comedy. Gradually, the film finds some momentary footing once it heads into "The Grudge" territory. A scene involving a urine bath and another in which a subtitled conversation is translated solely from speaking Japanese name-brands are very funny.

There are other isolated laughs too, including a cheeky ribbing of George W. Bush via the fictional President of the United States (Leslie Nielsen), but the jokes that work are like infrequent breaths of fresh air in between long periods of inhaling toxic fumes. The "Brokeback Mountain" material, for example, is mean-spirited and unnecessary (it isn't even a horror movie), while an extended sequence in which poor Leslie Nielsen goes nude is embarrassing and exploitative. You actually start to feel bad for Nielsen, whose aging body is used as the brunt of a joke without a punchline.

Once the setting switches to "The Village," "Scary Movie 4" plummets off the deep end and never recoups itself. The final thirty minutes, nearly laughless and actually boring, are an endurance test—something that no previous "Scary Movie" entry ever was. The actors are uniformly mismanaged, with not a single one of them put to a use that equals their capabilities. New male lead Craig Bierko (2005's "Cinderella Man") is pretty good at imitating Tom Cruise on the "Oprah" show, but a bland presence otherwise who doesn't share half the spark between Anna Faris' Cindy as Simon Rex (appearing here in a cameo) did in the last film. Meanwhile, Carmen Electra (2005's "Cheaper by the Dozen 2") and Chris Elliott (2001's "Osmosis Jones") play the Bryce Dallas Howard and Adrien Brody roles from "The Village," but with only two scenes and no involvement in the main storyline, they would have been better off calling in sick. With "Scary Movie 4," the first surefire sign of aging has reared its ugly head. What the series needs is another shot of fresh rejuvenation, even if that means losing director David Zucker. As is, it's just more of the same, only much, much worse. The past three films left the viewer feeling entertained, exhausted from laughter, or at least in good spirits by the end. "Scary Movie 4" simply leaves you feeling empty and depressed.