There is a bunch of experimental theaters here called A Bunch of Experimental Theaters.

They are neither on Broadway nor Off-Broadway. They are Off-Off-Broadway, located largely in the wilds of SoHo, south of Greenwich Village. They are often hard to find - physically as well as esthetically - but once you do track one down, you stand a chance of adventures rarely offered by the beaten path.

Bunch budgets are frequently low, but this doesn't prevent Bunch directors from exerting influences in cities around the United States and around the world. This happens whenever a Charles Ludlam takes a college-teaching post, or a Richard Foreman directs a smash-hit 'Threepenny Opera" on Broadway, or a Richard Schechner makes his Performance Group the first professional American theater to appear in India.

At such times the boundaries of theater art are stretched, and the so-called avant-garde creeps a little further into our everyday experience.

The Bunch organization was formed four year ago, to facilitate such practical matters as publicity, touring, and educational programming. Eight companies now belong. With eight guest groups they recently held a festival, allowing newcomers and old-timers alike to sample their sundry wares.

I attended eight productions, and was struck anew by the vigor, imagination, and sheer chutzpah - sometimes pantingly irreverent - that continue to characterize the fringes of the American theatrical frontier.

The Bunch members vary wildly in artistic approach and technique - from the feminist improvisation of the Cutting Edge to the sharp satire of the Ridiculous Theatrical Company, from the fragmented philosophizing of the Ontological-Hysteric Theater to the firm discipline of the Performance Group.

Amid these hectic divergences, there are threads that hold the Bunch together for expressive reasons, along with more mundane considerations. Charles Ludlam, director of the Ridiculous Theatrical Company, notes that Bunch groups tend to put beauty before business, preferring artistic freedom to box-office security. They also share a devotion to theater as a medium where, to paraphrase Ludlam, the magic comes from audience and artists having an experience together in a single time and place.

High on my festival must-see list was the Performance Group, which burst on the scene about 10 years ago and has maintained a strong, if off-beat, reputation ever since. Its concept of "environmental theater" has remained fresh since its debut with "Dionysius in '69," which tumultunously but memorably updated a Euripidean classic to fit the flexible Performing Garage on a particularly grimy SoHo street.

Its work has also been seen to tour well (the antic "Commune," for example) and has even been filmed with some success (as with "The Tooth of Crime").

For the festival, the group turned again to the past, offering Seneca's "Oedipus" - an odd choice of material, since this purplish Roman version of the legend has less built-in respectability than the superior Greek one of Sophocles, and was never intended to be performed in the first place.

The star of the evening was the environment by James Clayburgh, who built a miniature amphitheater rising steeply around a small stage area covered with 27 tons of dirt, in which the actors crawled, groveled, stomped, and occasionally buried one another. They also spoke the poetic text (as adapted by the gifted Ted Hughes) with such drive that words and phrases felt more like physical blows than floods of mythic insight. Richard Schechner directed, with an energy just short of explosiveness.

Upstairs at the Performing Garage, The Group offered a very different experience: "Rumstick Road," the second part of a trilogy called "Three Places in Rhode Island." The star was an actor named Spalding Gray, who portrayed himself and presented tape recordings of conversations with members of his real-life family. The subject was an inquiry into the actual suicide of his mother some 10 years ago.

Such a totally personal theatrical approach raises unsettling questions. Many spectators dislike being exposed to tragic autobiography that is utterly undisguised; one viewer said she resented "having to be this man's 'shrink.' "Exposing "the facts" of Gray's experience also brings about occasional references to religious beliefs he evidently neither shares nor understands, and some of the recordings were apparently not authorized for public use.

Yet "Rumstick Road" was haunting in its sincerity, penetrating in its insights into the meanings and mechanisms of memory, and movingly performed. It was also staged, by Elizabeth Lecompte, with a visual brilliance unsurpassed by any stage event in my memory. Looking past the hard questions they raise, she and Spalding Gray are two of the most promising young talents I have ever encountered.

"Oedipus" was to continue through Jan. 15, and perhaps beyond. The "Rhode Island" trilogy will conclude in early April with "Nayatt School." The group's next production will be "Cops" by Terry Curtis Fox.

Another leading light of the Bunch is Richard Foreman, whose Ontological-Hysteric Theater is now presenting "Blvd. de Paris (I've Got The Shakes)." The show has several alternate titles, as well - suffice to say they are as provocative, amusing, disjointed and pretentious as the work itself.

Foreman still has the theatrical drive and intellectual limberness that characterized his fabulous staging of the opera "Elephant Steps" in 1968. Though his sense of humor may have flagged a bit, he has an uncanny knack for stuffing mountains of spectacle into the murky recesses of a SoHo loft, and cramming 75 minutes with more meanings, obsessions, and lapses of taste than most avant-gardists ever dream of.

The play has to do with connections among thinking, feeling, knowing, and behaving. I suspect it must be seen to be believed, though Foreman has an arch habit of tossing out cryptic verbal hints about how we're supposed to take it. In all, an implosive evening that must be respected for its compulsively detailed expression of Foreman's turbulent artistic personality.

The Ridiculous Theatrical Company has attempted its own mini-spectacles in the past, such as the mock-pornographic "Bluebeard," but its festival offerings were more modest, if no more conventional. "The Ventriloquist's Wife" featured Charles Ludlam, the unique actress named Black-Eyed Susan, and a dummy called Walter Ego in a campy "psychodrama" designed for a cabaret setting (seen in preview at the Wonderhorse Theater).

Ludlam also revived his popular "Professor Bedlam's Punch and Judy," which my children and I found intermittently charming some years ago, and Bill Vehr gave an enthusiastic reading from a characteristically rhythmic section of James Joyce's "Finnegan's Wake."

In yet another change of pace, the Cutting Edge offered the improvisatory "Never Waste a Virgin" - the title refers to the Scheherazade myth - based on the shortest and sweetest section of John Barth's "Chimera." Its feminist insights were presented amiably and outspokenly, albeit unexcitingly. By contrast, the Ken Jacobs Apparition Theater showed little inspiration in its "Air of Inconsequence," a tired 3-D shadow show using polarized light effects.

One hopes the event helped more spectators learn the whereabouts of such exotic showplaces as the Wonderhorse and the Entermedia - not to mention Foreman's anonymous loft, which seems positively hidden away - and expanded all our expectations and appreciations at least a little bit.