The relentlessly (and overbearingly) quirky imagination of filmmaker Jared Hess yields diminishing returns in his third feature. While "Napoleon Dynamite" was carried by Jon Heder's offbeat charm and "Nacho Libre" by Jack Black's manic energy, "Gentlemen Broncos" has little to offer besides unrelenting strangeness. It pretty much peaks with its wonderful opening credit sequence, featuring a procession of mock paperback covers of sci-fi novels.

Such pulp fiction fuels the plot, which has to deal with oddball (what else) 17-year-old sci-fi writer Benjamin (Michael Angarano), who leaves his oddball mother (Jennifer Coolidge) behind at their geodesic dome house to attend writers camp. There, he meets his longtime idol, oddball sci-fi writer Dr. Ronald Chevalier (Jemaine Clement), as well as oddball flirtatious teen Tabitha (Halley Feiffer) and oddball aspiring filmmaker Lonnie (Hector Jimenez) -- oh, and oddball "guardian angel" Dusty (Mike White), who constantly carries around a large snake.

After Benjamin submits his novel, "Yeast Lords," to Chevalier, he is devastated when the apparently blocked author makes some minor changes to the text and passes it off as his own latest magnum opus.

Along the way, we are treated to a series of increasingly bizarre scenes from various versions of the sci-fi story, featuring a multi-wigged Sam Rockwell as the hero -- alternately dubbed Bronco and Brutus -- who at one point has his testicles removed by evil aliens.

It's hard to imagine who this film will appeal to other than the most devoted sci-fi geeks, and even they are likely to be unimpressed by the uninspired parody on display.

There are some amusing moments, mainly provided by the supporting cast. Coolidge, as usual, provides daffy fun as the popcorn ball-creating mother, and Clement -- miles away from his "Flight of the Conchords" persona -- is hilarious as the pretentious Chevalier, who constantly wears a Bluetooth headset even though he never makes a call.

There's no denying the affection that the filmmaker obviously holds for his collection of peculiar characters and their distinctive milieu, nor his eye for the sort of offbeat visual details that lends needed comic texture to the proceedings. But his vision, however authentic, here proves simply wearisome.

Opens: Friday, Oct. 30 (Fox Searchlight Pictures)
Production: Rip Cord
Cast: Michael Angarano, Jennifer Coolidge, Jemaine Clement, Mike White, Hector Jimenez, Halley Feiffer, Josh Pais, Edgar Oliver, Clive Revill, Sam Rockwell
Director: Jared Hess
Screenwriters: Jared Hess, Jerusha Hess
Producers: Mike White, John J. Kelly
Executive producers: Ben LeClair, Jerusha Hess, Jared Hess
Director of photography: Munn Powell
Production designer: Richard A. Wright
Editor: Yuka Ruell
Music: David Wingo
Costume designer: April Napier
Rated PG-13, 90 minutes