There is a sub-genre of comedy that Saturday Night Live alumni seem to specialize in which I've decided to dub the "wouldn't it be funny if" movie. The defining characteristics are as follows:

1) Begin with flimsy, 25-words-or-less premise. (Wouldn't it be funny if Will Ferrell wore a bad wig and a bushy mustache to play a phony-baloney male chauvinist news anchor in the 1970s?)

2) Expand on this premise and explore its comic possibilities only to the extent of creating an endless supply of sophomoric sex jokes. (Wouldn't it be funny if Christina Applegate played the country's first female news anchor, who threatens Ferrell's insecure manhood?)

3) Sit around a room with a bunch of writers and say "Wouldn't it be funny if..." until you have enough random, unrelated, one-off gags to fill up six reels of film plus closing-credits out-takes.

And 4) When said gags fall flat, cut the actors loose to mug furiously for the camera and loudly ad-lib attempted catch-phrases until somebody yells "Cut!"

Many a sketch-comedy veteran relies on "wouldn't it be funny if" concepts for their Hollywood livelihoods, and Ferrell is their current patron saint. He and rookie director Adam McKay (a former "SNL" head writer) co-wrote "Anchorman: The Legend of Ron Burgundy," in which the comedian plays an arrogant but inept, childish ninny of a blow-dried TV newsman (as opposed to all the other arrogant, inept, childish ninnies he's played in his career).

It's a movie with a few golden moments of out-loud hilarity (a "West Side Story" rumble between rival on-location news teams), with a healthy disrespect for the superficiality of local TV journalism (a pregnant panda is "the big story of the summer!"), and with a number of good laughs that don't translate well to print (Ferrell getting sex advice from his dog).

It also boasts another scene-stealing performance from "The Daily Show's" Steve Carell, who upstaged Jim Carrey as another conceited anchor in "Bruce Almighty" and here does the same to Ferrell as a blundering weatherman with an IQ of 48. And without having to steal anyone's thunder, Applegate continues to prove how much better she is than her material, bringing real character to her underwritten role (just as she did in 2002's "The Sweetest Thing") and giving better than she gets in verbal cat fights with Ferrell.

But while McKay has a sharp eye for both broad chuckles and comedy minutia (the gung-ho Texan sports reporter on Ferrell's show looks vaguely ridiculous because his cowboy hat is a couple sizes too big for his head), even at its best the movie's inconsistent clowning cannot make up for the fact that "Anchorman" relies on empty-headed conventionality for its story structure.

Just once couldn't we have a movie in which the intelligent, beautiful, self-possessed female lead -- who is clearly, and in every way, superior to the dense, immature self-centered male lead -- does not forgive him an entire litany of unfixable faults to make for a so-called happy ending? I mean, does Will Ferrell really think audiences will care enough about this unlovable jackass that they'd be disappointed if he didn't get the girl?

Good dumb fun can be lowbrow without being lazy (see "Dumb and Dumber," Ferrell's own hit Christmas comedy "Elf," or the upcoming stoners-with-the-munchies road-trip flick "Harold and Kumar Go to White Castle"), but bite-sized episodes of creative lunacy are not by themselves enough to qualify "Anchorman" as the kind of dumb worth paying to see.