"Thank God It's Friday" takes place at a disco club in Los Angeles called The Zoo. The general idea is that The Zoo is the latest and greatest place to go, a dancehall whose atmosphere is indisputably stimulating and fashionable.

The actual effect is remarkably different: After 90 aimless, alienating minutes among the menagerie of TV sitcom-pilot boors, half-wits and low-lifes congregated at this would-be flashy nightspot, one craves something a shade finer. Maybe the neighborhood saloon or the miniature golf course or the library.

Most movies turn into period pieces as the years go by. Some misbegotten movies seem dated when they're first released. "Thank God It's Friday" is the most conspicuous recent example of instant obsolescence. You realize it's meant to illustrate and glamorize and up-to-the-minute setting, but you end up feeling that the disco craze must be some antiquated fad, like marathon dances, six-day bicycle races and flagpole-sitting.

Triteness is one of the problems. Episodic scenarios in which several characters intermingle are frequently effective; for example, "American Graffiti," "Nashville" and the recent satirical comedy about Beatlemania, "I Wanna Hold Your Hand." The characters who fit through "Thank God It's Friday" don't sustain a glimmer of human interest. When attention shifts back to one character or set of characters previously introduced, you have trouble placing them.

The most prominent faces in the crowd are Jeff Goldblum, the fine young actor of "Between the Lines" and "Next Stop, Greenwich Village," as a lecherous proprietor; Ray Vitte as a slightly frantic disc jockey; Donna Summer as an aspiring singer; Mark Lonow and Andrea Howard as a suburban couple who flirt with adultery; Chick Vennera as a Chicano with dancing feet; Valerie Landsburg and Terri Nunn as teen-age crashers, and Hilary Beane and Chuck Sacci as computer mismatch.

Goldblum looks amusingly self-confident in his first few scenes, but he doesn't manage to finesse director Robert Klane's apparent demand for exaggerated responses. Klane seems especially dependent on eyes opening wide to convey wonder or disbelief. The actors work like demons to keep those eyes way, way open.

A co-production of recording companies, Motown and Casablanca, the film spins a multitude of excerpts from the backlog of performers under contract to both labels. Summer and The Commodores, who make a guest appearance as themselves, are with Casablanca. Awkward and unappealing when she's meant to be acting, Summer does come alive when she gets one chance to sing a live number.

Although 32 songs are listed in the credits, almost all become background noise that goes in one ear and out the other. Like "FM," "Thank God It's Friday" illustrates the illegitimate way of wedding movies and LPs. The soundtrack albums of hit films like "American Graffiti" or "Star Wars" or "Saturday Night Fever" genuinely recall and supplement the stimulation people derived from the films. "FM" and "TGIF" are flimsy cinematic pretexts for over-sized LPs.

Vennera is given a strenuous dance solo in a parking lot that is neither well-staged nor well-shot but does suggest a throwback to the film musicals of a generation ago. The idea of such a number, highlighted by jumps from one car roof to another, is nostalgically as well as kinetically stirring. Unfortunately, it's also a futile, inappropriate lyric gesture in the context of a musical as heavy on its feet as "Thank God It's Friday."