The art of theater has flourished for thousands of years, but it never runs out of room for experimentation. Three talented artists have combined to realize two separate but conceptually related experimental pieces by Rick Burkhardt as part of the New York Frigid Festival.

Great Hymn of Thanksgiving, which takes up the first third or so of the hour-long show, bridges the gap between musical and meta-theatrical performance. Three actor-musicians - Burkhardt, Ryan Higgins, and Andy Gricevich - sit around a table playing percussion and sometimes vocalizing. A few of their instruments are standard ones - cymbals, a zither, a triangle - but they're often not played in the usual way, and much of the sound comes from objects "found" at the table - dishes, cutlery, bowls, and glasses filled with water.

One gets the sense that there's some internal logic to the sequence of quiet, slow sections and loud cacophonies of rattling and table-pounding, but if there is, it isn't easily teased out. It doesn't help that one loses patience during some of the near-silent sections. The spoken parts include evocative elements such as a quiet litany of Iraqi war dead, but these seem cobbled in with little if any context. On the whole, it's an interesting piece that has one at the edge of one's seat at times, but would have more impact if it stepped more lively, or were compressed into a shorter time-frame.

The Iraq war references take on more meaning as the second part begins. Conversation Storm is a play about three high school friends, now in their thirties, sitting in a restaurant revisiting the intellectual debates of their youth with a discussion about whether torture is ever justified. Self-consciously acting in a play, giving each other director's notes and stage directions, and lecturing the audience, they dig ever deeper into a psychological game where they try to break each others' will until it no longer seems a game. Nightmarish imagery and plain sophistry are both enlisted to challenge moral principles; we are gripped; tables turn. But the deliberately fractured action careens between genuinely dramatic intensity and inexplicable weirdness.

Like the musical portion of the show, this part would benefit from some tightening up; I frequently lost patience with the insistent distractions from what the characters were actually doing to each other, especially in the latter part of the play where it stopped making an effort to engage the audience. No doubt Burkhardt is diluting the emotional power of his piece on purpose. But if it is to make a statement, I wasn't sure what the statement was (perhaps the dehumanizing effect of torture, but that hardly needs saying) - and if it was primarily for effect, the effect was disconcerting and not always engagingly so. All experiments are valid in art, and theater - the most visceral and potentially powerful of all the arts - is ground zero for the cutting edge. But this edge didn't cut evenly.

Presented by Horse Trade and EXIT Theater, through March 9 in repertory at the Frigid Festival. At the Kraine Theater, 85 E. 4 St. (across the street from La Mama).