The blue-collar misfits of "Mystery Men" might have been super-heroes had they lived in the heyday of John Henry, Paul Bunyan and Pecos Bill. In those days, more prosaic skills--steel-driving, lumberjacking, bronco-busting--were the stuff of legend.

Sadly, the ragtag crew of this fond but sluggish send-up was born into a virtually crime-free society, where their neighbors scoff at their delusions, and their inept attempts at fighting crime do more harm than good. After an especially embarrassing episode at an old-folks' cabaret, they are on the verge of disbanding when disaster strikes.

Captain Amazing (Greg Kinnear), Champion City's super-hero in residence, is captured by a recently pardoned nemesis (Geoffrey Rush, utterly wasted in the role), who intends to kill the good captain before destroying the once-peaceful metropolis. All that stands in his way are the Mystery Men.

Of the seven flaky avengers, only the Spleen (Paul Reubens) possesses a weapon as lethal today as in bygone days. The pimply, pasty-faced Spleen gases his enemies with great clouds of toxic flatulence, on command and precisely aimed.

The group takes its cues from founding member Mr. Furious (Ben Stiller), a postmodern Walter Mitty who thinks of himself as a "ticking time bomb of fury." In truth, he wouldn't dare talk back to his odious boss or the smart-alecky cops who frequently harass him and his lieutenants: the Shoveler (William H. Macy), a hangdog Everyguy armed with a spade, and the Blue Raja (Hank Azaria), a foppish flinger of spoons and forks.

New recruits include Invisible Boy (Kel Mitchell), an enthusiastic teen who becomes transparent, but only if no one is looking at him, and the Bowler (Janeane Garofalo), the group's only superwoman. She strikes down her adversaries with a translucent ball containing her late but still kibitzing father's skull.

Based on the Dark Horse Comics series, "Mystery Men" is essentially a live-action cartoon without dramatic focus, a solid structure or discernible theme. The concept has plenty of comic potential, but the truth is, hitting somebody with a shovel really isn't as funny the fourth time around.

Debuting director Kinka Usher, the adman who gave us the Taco Bell spokesdog and the "Got Milk?" commercial, doesn't know when enough is enough already. Scenes that are initially funny overstay their welcome. And Usher can't get enough of obtrusive, action-disrupting wide-angle and fish-eye lenses.

Although the movie's too long and the material is too sparse, the actors portray their eccentric characters with goofy earnestness and plenty of pluck. Alas, not one of them is essential to the tale.

Certainly screenwriter Neil Cuthbert ("Hocus Pocus") was unable to settle on a single point of view. That's probably because when you get right down to it, the Shoveler, the Spleen, Mr. Furious and crew are all variations on a theme. And for all the movie's camp chic, its message is a pretty corny one of follow your dream.

Mystery Men (121 minutes, at area theaters) is rated PG-13 for comic violence.