La Mama is the long-running champ of experimental theater, now celebrating its 25th year of shaking up traditional stage ideas. It's hard to think of a better anniversary event - in terms of summing up La Mama's spirit - than its current revival of ``Fragments of a Greek Trilogy,'' a work based on three plays by Euripides, enhanced with music by Elizabeth Swados, and directed with staggering imagination by Andrei Serban.
This production first graced La Mama a dozen years ago, when ``environmental theater'' was a buzzword.
Directors were then working nonstopto discover new kinds of settings for their shows, and often to break the invisible barrier separating actors and audience.
Many such efforts seemed forced or arbitrary. But some productions between the late '60s and middle '70s used ``environmental'' ideas to bring a new visual and kinetic excitement to their texts.
Besides much work by the Living Theatre and the Open Theatre, key examples include Richard Schechner's staging of ``Dionysus in '69,'' based on ``The Bacchae'' of Euripides, and Tom O'Horgan's lively ``Hair,'' which became a Broadway classic.
``Fragments of a Greek Trilogy,'' a free adaptation of Euripides spoken in a ghostly blend of Greek and Latin, stands with the giants of its genre.
It begins with a 55-minute-long rendition of ``Medea'' that's as much a musical as a theatrical experience. For its first portion, the audience stands along a candle-lit hallway in La Mama's basement, where performers pass among them uttering harshly sibilant words.
Then everyone enters a small, dank room where Medea's tale of betrayal and revenge is completed with spare gestures and ferocious syllables that evoke the atmosphere of an obscure but urgent ritual. A battery of percussion instruments, tightly packed into one corner, adds to the crashing power of the experience.
``The Trojan Women'' is less intense but more explosive. It starts in the lobby, where the performers stage a parade. Following them into the large space of the La Mama annex, the audience moves from one curtained-off area to another, encountering a series of extravagant theatrical effects - among them a barbaric dance, a savage execution, a death followed by a slow-motion fall to earth.
Only in the play's second half do the spectators take seats, which are still in harrowingly close contact with the action.
The trilogy's last portion, ``Electra,'' makes for a stately conclusion, if not an exhilarating climax. The round tones of hand-held bells now punctuate the text as performers pass between the mainstage and high platforms via wooden ladders, moving with stylized eloquence while still intoning their lines in a rich blend of ancient tongues.
In conceiving and staging this production, Serban's inspiration has been to emphasize the primeval emotions and beliefs that lay just behind the elegant fa,cades of ancient Greece - which for all its greatness as a civilization was, after all, just one step away from the untrammeled superstition and barbarism of primitive humanity. In so doing, he has touched chords that reverberate with stark power more than a decade after they were first sounded on La Mama's stages.
``Fragments of a Greek Trilogy'' continues through March 15.