Shlemiel the First (Geffen Playhouse; 498 seats; $ 37.50 top) Geffen Playhouse, in co-production with the American Repertory Theatre and the American Music Theatre Festival, presents “Shlemiel the First,” a musical play in two acts based on the stage play by Isaac Bashevis Singer, conceived and adapted by Robert Brustein, directed and choreographed by David Gordon. Music composed, adapted and orchestrated by Hankus Netsky; musical direction, musical arrangements and additional music by Zalmen Mlotek; lyrics by Arnold Weinstein; scenic design, Robert Israel; costume design, Catherine Zuber; lighting design, Neil Peter Jampolis; sound design, Christopher Walker. Conductor/pianist is Michael Larsen. The Golden State Klezmers Band: Zinovy Goro (clarinet), Ezra Kliger (violin), Laroon Holt (trumpet), Daniel Weinstein (trombone), Richard Bernard (mandolin/guitar), Vic Koler (bass), John Harvey (percussion). Opened and reviewed May 14; runs until June 8. Running time: two hours. Cast: Alice Playten (Tryna Rytza: Mrs. Schlemiel), Thomas Derrah (Schlemiel), Maureen McVerry (Yenta Pesha), Charles Levin (Gronam Ox), Will LeBow (Zalman Tippish), Benjamin Evett (Chaim Rascal), Remo Airaldi (Mottel), Vontress Tyrone (Zeinvel). Ensemble: Victor Buno, Wendell Doodrum, Al Nowicki, Arianna Ortiz. Aside from the quirky, Chagal-like set design of Robert Israel, the surprisingly understated Geffen Playhouse presentation of “Schlemiel the First” doesn’t nearly capture the zany, wildly caricaturized lunacy of Yiddish/Jewish burlesque , but Netsky’s Klezmer-based musical score — brilliantly realized by pianist Michael Larsen and the seven-piece Gold State Klezmers — is pure joy. Based on late Nobel Prize-winning author Isaac Bashevis Singer’s 1974 stage play adaptation of timeless Jewish folk tales (commissioned by current American Repertory Theatre artistic director Robert Brustein for Yale Repertory Theatre), “Shlemiel the First” brings to life the inhabitants of the mythical shtetl of Chelm, which is ruled by the pompous and silly self-anointed wiseman Gronom Ox (Charles Levin) and his even more inane council of five. Furthest down in the village’s pecking order are simple and oblivious Shlemiel (Thomas Derrah) and his hard-working, long-suffering wife, Tryna Ritza (Alice Playten). When the Gronom Ox and the council send him to travel around the world to spread the word of the council’s wisdom, the gullible Shlemiel (Yiddish for “fool”) is soon tricked by the impish Chaim Rascal (Benjamin Evett) into retracing his steps back to Chelm. Thinking he has discovered a duplicate Chelm, occupied by villagers and a Mrs. Shlemiel that looks exactly like the first, Shlemiel launches into a series of misadventures that includes convincing the council that there must be two Shlemiels and committing adultery with the woman he considers to be Mrs. Shlemiel the second. More than the story, it’s the storyteller that’s key to this work. Akin to comedia dell arte, the humor is based on time-honored characteristics and idiosyncrasies; as hard-working and energetic as this cast is, they fail to pump the piece with life. This is particularly true of Derrah in the title role. His Shlemiel comes off more undernourished than simple, particularly in his near-feeble vocalizing on “Beadle with a Dreidel.” Another missing ingredient is the supposed raucous slapstick that should be inherent in the interplay of the Chelm council (Remo Airaldi, Maureen McVerry, Will LeBow, Vontress Tyrone, Benjamin Evett). Under Gordon’s careful staging, their actions are more studied than comedic. The one exception is Airaldi’s gleefully inept Mottel. Levin comes the closest to capturing the spirit of Yiddish theater in his larger-than-life portrayal of Gronam Ox. He exhibits immaculate comic timing, especially in his ongoing confrontations with his pickle-wielding wife, Yenta, played with zany irreverence by McVerry. The musical highlight of the evening is the Levin-led production number of that time-honored Jewish vaudeville patter-song, “Rumania, Rumania.” Also effective is LeBow’s brief but hilarious portrayal of the wealthy Zalman Tippish (“He’s Going To Die”). As the only truly sane member of the community, Playten’s Mrs. Schlemiel exudes a wonderful blend of compassion, resignation, exasperation and love for her life-limited mate. Her vibrant voice invests a world of emotion in her renditions of “Wake-Up Song,” and “My One and Only Shlemiel.” The real plus of this evening, however, is the klezmer-mad instrumental ensemble, headed by Michael Larsen and the soaring clarinet/violin interplay of Zinovy Goro and Ezra Kliger, respectively. If the whole production were infused with the same virtuosity and energy exhibited by the backup musicians, “Shlemiel the First” would really be something.