If Charlie Brown, Stephen Dedalus, and Bart Simpson’s friend Milhouse have taught us anything, it’s that trauma is funny, adolescent trauma is funnier, and sensitive, intelligent adolescent trauma is funnier still. With its lofty parental expectations, inconvenient priapism, and six-syllable words, “The 25th Annual Putnam County Spelling Bee” is downright hilarious.

William Finn and Rachel Sheinkin’s musical, which opened at Second Stage last night, makes us the audience for the eponymous smackdown in the gym. Six kids from area schools – hormonal Boy Scout, whiz kid with two daddies, home-school eccentric, etc. – compete for big rewards. There’s a trip to the national spelling bee at stake, and a savings bond, and confirmation that what other kids say about their limited worth may not be true after all.

Consider: A shy waif in pink overalls named Olive (the excellent Celia Keenan-Bolger) sings very sweetly about “My Friend, the Dictionary.” Logainne Schwartz and grubenierre (Sarah Saltzberg) is the head of the gay, straight, bisexual, and transgender alliance at her elementary school, but feels such pressure from her dads that she still sings “Woe Is Me.” William Barfee (dangerously funny Dan Fogler) – poor chubby William with his bad sinuses and worse hair – uses his “Magic Foot” to spell words as he slides across the floor, a trick that led him to last year’s nationals. Alas, vicious food allergies there rendered him a L-O-S-E-R.

It’s a talented bunch of performers, you may be noticing – and these are just the ones getting paid to be onstage. (The crack lineup also includes golden-voiced Jose Llana as the newly pubescent defending champ, and terrifically funny Jesse Tyler Ferguson as the hippie kid who makes his own clothes.) Director James Lapine also fills the ranks of contestants with audience volunteers, a cheap, cheesy gimmick that works brilliantly.

The stream of new faces heading to the microphone gives the event host, past champion Rona Lisa Peretti (Lisa Howard), plenty of opportunities for comic spontaneity. At least, Ms. Howard’s introductions sounded like improv, as when she said that the favorite TV show of a volunteer with floppy, Scott-Baio hair was “Joanie Loves Chachi.” Of course, audience interaction can be tricky – as vice-principal and word reader Douglas Panch (Jay Reiss) discovered the night I saw the show. He had to dig very deep in his bag of impossible words to knock out some woman who sounded like Off-Broadway’s answer to Ken Jennings. All this loose, spunky energy – I haven’t even mentioned a brief appearance by Jesus on the cross – makes the show a real delight.

But now we must be stern. Duty compels me to roll up my sleeves – yea, fold the tweed up to the elbow patches – and dispense some Drama Criticism. Ms. Sheinkin has written one of the funniest libretti in years. Still, its raucous humor from line to line can’t mask certain larger troubles, like a failure to build comic tension. She introduces a parolee who’s working as a “comfort counselor” (Derrick Baskin) to fulfill his community service requirement, a hugely promising device that gets wasted. (Why isn’t anyone menaced by him? Why doesn’t he toss off snide remarks throughout?) Also there’s the question of intermission, which I gather has come and gone during previews. The show was performed without one when I saw it, but it was plainly written with one in mind. Now the pace is off: You feel the non-intermission like a phantom limb.

Mr. Finn’s giddy, complex music captures the anxieties of youth, but his lyrics are frequently a dud. “Magic Foot” goes nowhere in particular, and Olive’s epic number about her absent parents wanders too far. The creators had a smart idea in giving the hyper talented Asian girl Marcy Park (Deborah S. Craig) a song to lament the fact that “I Speak Six Languages.” But as she dances, twirls the baton, and accompanies herself at the piano, the number doesn’t accumulate the right manic energy.

The musical has come a long way already, from the original show conceived by Rebecca Feldman Off-Off-Broadway, to an out-of-town run, to this one Off-Broadway. At its best moments – during, say, the onstage antics of Mr. Fogler and Mr. Ferguson, or the sharper lines from Ms. Sheinkin’s book – it has the glimmer of “Avenue Q,” an obvious influence. Another round of rewrites and it may enjoy the same well-deserved acclaim.

***

Arliss Howard has replaced Sam Shepard in “A Number,” and the results are even more striking than I’d hoped. Caryl Churchill’s two-hander about a father and three of his sons (two of whom are clones of the original), left me cold when it opened in December at New York Theatre Workshop. It seemed slight, aimless: two words I don’t normally associate with one of the most brilliant and provocative playwrights alive.

Returning over the weekend, I saw that Mr. Howard has brought greater clarity and higher emotional stakes to the stage. He goes much further than Mr. Shepard in making Salter a second-rate man: gruff, self-involved, slightly bumbling. The play has become a more resonant study of parental guilt and responsibility, and the desire for second chances.

The laconic Mr. Shepard rarely got past Salter’s bewilderment at learning that a doctor had made “a number” of clones from his son’s genetic material. Mr. Howard manages to expose how deeply guilty he feels. When Mr. Shepard said that he wanted to call a lawyer because he might be owed some money, it seemed like emotional deafness. Mr. Howard makes all the lawyer talk sound like a desperate attempt to make right something it was beyond his power to make right. It was unexpectedly moving.

In fact, Mr. Howard has done so much to improve the production that its shortcoming now seems to be his costar. Dallas Roberts is an exceptionally talented young actor who, here, is trying way too hard. Switching from one son to another, he pivots from an exaggerated fear and confusion to a quietly manic psychosis. Playing against Mr. Shepard, all the energy was useful: The show needed some kind of propulsion. Onstage with the nuanced, grieving Mr. Howard, it distracts.

I doubt that James MacDonald’s mannered staging could do justice to Ms. Churchill’s remarkable play, no matter who’s in it. But in making so much clearer what Salter has lost, Mr. Howard brings the show closer to what I imagine she had in mind. It is a major play after all.

Until March 6 (307 W. 43rd Street at Eighth Avenue, 212-246-4422).