After his flamboyant exertions on "Carrie" and "The Fury," Brian De Palma decided to take a vacation from thrillers.

He ended up returning to his original forte, comedy, in an academic setting.

The result is "Home Movies," a diverting little satire about the triumph of a frustrated kid brother growng up in a family of egocentric, loony "role models" -- philandering pop, self-pitying mom and pompous big brother -- which begins a limited engagement today at the Key in Georgetown.

De Palma began making short films in the early 1960s while he was a graduate student at Sarah Lawrence College. "Home Movies" grew out of a course he agreed to teach there in 1978. De Palma contributed the plot outline, and the screenplay was improvised in collaboration with half a dozen students.

The crew was composed of students and aspiring filmmakers who volunteered their services. De Palma put up part of the investment and attracted other investors, including actor Kirk Douglas, who had played the lead in "The Fury."

Douglas also contributed a delightful, self-parodistic cameo to "Home Movies," playing a dynamic self-improver known as The Maestro who advocates a doctrine called Star Therapy, which involves shooting amateur films with yourself in the lead in order to "bring yourself into focus" and cease "being an extra in your own life."

The story is loosely organized as a case history of The Maestro's most vexing pupil: a high school senior named Dennis Bird, played by the canny, charming young actor Keith Gordon. Although he tries to ingratiate himself, Dennis can't seem to attract the attention of his preoccupied parents -- Vincent Gardenia as the lecherous Dr. Bird and Mary Davenport as his weepy, resentful wife. Dennis also fails to impress his older brother James, mom's darling. But then James (played by Gerrit Graham with his jawline always jutting mock-heroically and his curly locks stirring to impossible breezes indoors) is impressed only by his own sense of self-importance. James envisions himself as the prophet of a crackpot neo-Spartan creed he calls Spartanetics, designed to train a rejuvenated, mystical, latently homosexual brotherhood of Manly Men to restore civilization to valor and virtue.

Dennis flunks the Star Therapy course, but gets even with the intimidating James by alienating the affections of his fiancee, Nancy Allen as an instinctively sweet, carnal dreamgirl named Kristina, who's losing her grip as James browbeats her into submissive shape. The alienation is well-deserved and highly satisfying, because Keith Gordon and Nancy Allen have a marvelous romantic comedy rapport. (Introduced in "Carrie" as the scheming high school vixen, Allen also became Mrs. De Palma shortly after "Home Movies" was made.) They seem magically, humorously right for each other from the first moment De Palma links them on the screen, showing Allen approaching in rapturous, lushly backlit slow motion while Gordon stares at her transfixed, his mouth curled into a goofy lustful smile and one hand absent-mindedly mashing potatoes.

De Palma paired Gordon and Allen again in "Dressed to Kill," but this initial appearance is even more agreeable. The rightest things in the movie are their scenes, which establish an irresistibly funny, ingenuous intimacy. De Palma has always been astute about young performers, and this match is one of his nicest discoveries.

Although it's a highly professional low-budget improvisation, "Home Movies" may seem disappointing if you make the mistake of expecting any kind of big deal. It's best appreciated as a casual small entertainment, but at the moment it may enjoy an extra comic dimension because of the prominence of Robert Redford's "Ordinary People." While it was made first, "Home Movies" now seems like a burlesque on the themes of parental indifference and sibling rivalry exploited for conventional pathos in "Ordinary People."

"Home Movies" isn't as sharp or fluid as De Palma's previous satiric comedies, "Greetings" and "Hi, Mom!" (the difinitive movie satire on the pretensions of militant countercultural youth) and "Phantom of the Paradise." The ensemble isn't quite as well-balanced as it should be: One craves more of Douglas and Gardenia and less of Davenport and Graham, whose talents seem strained.

The comic attack is hit-and-miss, and ultimately the whole movie seems like a bubble, but it's certainly the freshest, funniest inconsequentiality to appear in many weeks.