This is a rousing year for the Wooster Group, a tremendously exciting theater company that deserves much more attention than it usually gets. After years of teetering on the edge of poverty, the troupe has received a major grant from the National Endowment for the Arts, as part of an NEA effort to establish and strengthen theater ensembles. Beginning with a $170,000 contribution for the 1985-86 season, this support will solidify a company that has been buffeted by money problems - most notably when the New York State Council on the Arts slashed its aid after a Wooster piece called ''Route 1 & 9 (The Last Act)'' stirred up political as well as aesthetic controversy.
And now, as if to celebrate its new security, the group has opened its most astonishing theater piece in years, a multimedia show called ''L.S.D. (...Just the High Points...).''
Despite its title, the work doesn't dwell on drugs, but uses them as an intermittent metaphor. Built in four sections, it explores two periods of social and moral unrest in the United States: the ''beat generation'' and ''psychedelic'' time of the '50s and '60s, and the witchcraft hysteria in Salem, Mass., during the 1690s.
As always, the group approaches its subject intuitively, brushing over history in search of a deeper, more idiosyncratic view than ordinary facts and fictions can provide. Developed by the performers under the direction of Elizabeth LeCompte, the result is a visionary epic of explosive brilliance.
Like all Wooster Group shows, ''L.S.D.'' doesn't bother with the usual rules of theater. Don't look for conventional story, dialogue, or characters. And don't expect the actors to act. Instead, focus on the nonstop cascade of images and ideas that bounce off one another within the ingeniously designed setting. And be ready for the performers to slide in and out of roles, treating the stage as a laboratory-playground where familiar formats take on uproarious new shapes.
I'll try to give some idea of what happens in the show, though there's no way to capture its unearthly resonance and overwhelming momentum. The players sit at (or under) a long table on a high platform. At first this resembles the dais of a hearing room; later it breaks open to become an outlandish parlor; and finally an off-kilter cabaret stage.
In the first section, performers read at random from books of the '50s and ' 60s by Aldous Huxley and Jack Kerouac, among others. Sometimes they act out their selections. At one side a ''baby sitter'' drones a silly narration full of phony and irrelevant information. The mood is casual, unpredictable, funny.
The second section is the thunderbolt of the evening - a zany performance of Arthur Miller's play about the Salem witch trials, ''The Crucible,'' in a radically Woosterized form. The troupe throws out most of the plot and characters, distilling the drama into pure energy and emotion. Each actor has a different style: Some give naturalistic portrayals; one does a scathing parody of racial stereotypes; others spew their dialogue so fast that sentences become percussive riffs with irresistible rhythms. The result is a seething mixture of bitter comedy and slapstick tragedy, crammed with indelible images and stunningly original stagecraft.
Part 3 transports the ''Crucible'' performance to a spaced-out living room of the 1960s, where the Salem witch hunt competes with stoned self-indulgence and more prattle from the baby sitter. The play disintegrates before our eyes; the mood grows dark and fuddled - and suddenly the performers become a rock band pounding out nostalgic songs while a leftover Salemite swirls in crazy circles on the stage.
In the last section, just one line from ''The Crucible'' remains - the words ''What is this dancing?'' etched on a pair of TV screens. Performers read a brief excerpt from the recent real-life ''debates'' between psychedelic guru Timothy Leary and Watergate figure G. Gordon Liddy, while an implausible quartet called Donna Sierra and the Del Fuegos do a nutty fandango. Liddy recites a smutty poem, Leary parries questions from an invisible audience, and the lights fade.
What does it all add up to? Many literal meanings weave through the show. On one level, it underscores Miller's original purpose in writing ''The Crucible'' - to criticize the anticommunist witch hunts of the 1950s - and extends the metaphor into the present. On a deeper level, it probes the nature of all national hysterias which grow from wormy fads to haywire mass movements.
Much more to the point, though, director LeCompte and her troupe are confronting the outer limits of theatrical invention with unprecedented wit and skill. Working as a tightly knit unit for years, they have developed a shared vocabulary of word and gesture that digs beneath literal representation, uncovering allusions and assumptions that surface more readily in dreams than in ordinary ''representational'' art.
''L.S.D.'' marks a bold step forward in the Wooster Group's continuing exploration of what theater can do when stretched into a new dimension by aesthetic wizards who reject the notion of conventional limits. The show is having an open-ended run at the Performing Garage in SoHo.