There is a renewed spiritual energy among young American Jews, and, surprisingly, the mechanism being used to harness it is the same institution from which many American Jews ran away after the age of 13. Yes, the synagogue, which once teetered on the edge of irrelevancy in the minds of young, self-described "spiritual" and "cultural" Jews, is attempting a comeback. Once written off for its boring and incomprehensible services and ineffectual religious schools, the synagogue was, not too long ago, considered a place of ritual and maybe nostalgia, but hardly of spirit. Today, that may be changing.

But while the various streams of Judaism are trying to harness the energy of the Jewish spiritual and cultural renaissance, this is no easy task, since this renaissance originated outside the major synagogue movements. The Reform, Conservative, and Orthodox labels are growing less meaningful, and we're entering a new "transdenominational" world, say Jewish leaders who study and attempt to tap into synagogue renewal.

The much-publicized recent acrimony between the ultra-Orthodox and the more liberal streams of Judaism, say many younger Jews, is largely irrelevant to them. They'll take what they want from any or every kind of Judaism--from Hasidim to humanism and anything in between--in this new spiritual salad bar.

What will replace the denominations, then? Jewish leaders seem to agree it has something to do with that word, "spirituality." But no one is quite sure what that means or how to create it. The most wonderful thing about this "spirituality" is that its definition can be bent, stretched, and morphed to fit any agenda.

Many Jewish leaders agree with three words spoken recently by Ron Wolfson, principal investigator for the Reform movement's Synagogue 2000 project. What defines great, spiritual davening (praying) experiences, he said, is "music, music, music."

Linda Freedman of Los Angeles is a thirty-something Jewish professional who ran away from Judaism when she was younger. She is now rediscovering a spiritual side she never learned in shul (synagogue) when she was growing up. Music that inspires--a kind of Jewish gospel music--would get her back into synagogue, she said.

The model everybody points to is Congregation B'nai Jeshurun in Manhattan. It's filled to the rafters with Jews of all denominations at its music-packed Friday night services.

But even B'nai Jeshurun's head rabbi, Marcelo Bronstein, admits that he does not know where to go with this spiritual energy that his shul has unleashed. B'nai Jeshurun works for the young, trendy Upper West Side Jewish crowd in Manhattan, but may not work elsewhere.

For every Jew, for every congregant, there is a slightly different definition of this vague concept of "spirituality" and how synagogues should reflect it. Some use music and dancing and place the bima (podium from which prayers are led) in the center, some emphasize social action programs, and some have clubs for young, hip Jews who are into the Jewish social scene. Others just want a welcoming environment and a good Hebrew school to send their kids to, or an intellectually stimulating environment. The synagogue of the future needs to be flexible enough to keep the interest and passion of a wide range of Jews.

Even Jews who revel in their disbelief in God--yet still define themselves as Jews--say they have a place in the grand parade of individually defined Judaism. And, perhaps surprisingly, in the synagogue, or at least some synagogues.

Secular Humanistic Jews bill themselves as "a bold option for modern Jewish identity." They attempt to organize into a religion those who have no use for organized religion. They discard the concept of God and define Jewishness as a sense of shared history, of passion, of justice, of collective memory.

Yet there is also what could be described as a "spiritual" fervency to their beliefs. It is a celebration of, indeed worship of, humanity and nature.

Secular Humanism represents "a real honesty about the sometimes sad, sometimes imperfect nature of our humanity" and, along with that, a "commitment to be honest together," said Greg Epstein, 23, of Ann Arbor, Mich., who recently gave up a career in rock music so he can study to become a Secular Humanist rabbi.

Epstein said he identifies strongly as a Jew because he is "proud to identify with a culture and a civilization that has had such a profound impact on human life."

This impact goes well beyond the secular, pop-culture Jewish icons of bagels, klezmer music, Madonna-style Kabbalah, and Jewish television comedians. The food, the minor keys, the New Age mysticism, the Jewish comedy shtick--these are remnants of Eastern European, New York, and American culture that have little to do with the "practice" of secular Judaism.

The impact Epstein said he's referring to is a Jewish commitment to work together toward the betterment of all humanity.