“It Shoulda Been You” is awfully funny. That’s strange, because there’s nothing especially clever about this musical comedy by Brian Hargrove (book & lyrics) and Barbara Anselmi (music), helmed by David Hyde Pierce in his Broadway directorial debut. The characters are broadly caricatured comic types you might find at a sitcom wedding (overbearing Jewish mother, high-strung bride, alcoholic mother of the groom, flamboyantly gay wedding planner, etc.), and instead of saying “Comedy Tonight!” the music says “Take a Nap!” But with impeccable instincts for finding their laughs, Hyde Pierce and his terrific ensemble players make this hokum seem terribly amusing.   

Bright lights go up on a staging area in the elegant hotel where the lavish Steinberg/Howard wedding will be held that afternoon. It will serve as the bedrooms of members of the wedding party, along with the beauty salon, various service areas and the ladies room where the bride tries to hide when she gets cold feet. Anna Louizos’ two-tiered stage is designed for farce, providing plenty of doors to slam, closets to jump out of, and toilet stalls to throw up in, once the wedding preparations become complicated.

A smartly staged opening number introduces the hackneyed characters and the super character actors who almost convince us that they’re fresh and funny. There’s the battle-ax mother of the bride (Tyne Daly, our queen of comedy), the bride’s beleaguered father (Chip Zien, a perfect piece of casting), the groom’s lush of a mother (Harriet Harris, always amazing), the groom’s stern father (Michael X. Martin, kinda stiff), the best man (Nick Spangler, nothing special) and the best woman (Montego Glover, very special), the gay-as-a-goose wedding planner (Edward Hibbert, as we know and love him), a couple of hotel staffers (Adam Heller and Anne L. Nathan, reliable old pros), and, of course, our bride (the stunning if undervalued Sierra Boggess) and groom (hunky David Burtka).

At the calm center of all the chaos is the bride’s older, unmarried sister, Jenny, a “big-boned girl” as the euphemism goes, played with as much heart as humor by Lisa Howard, who delivers a strong belt and deserves her moment in the sun after all the replacement jobs she’s had. And look! Here comes the bride’s geeky ex-boyfriend, played by Josh Grisetti, a perfectly wonderful physical actor who also deserves a break, after Neil Simon’s “Broadway Bound,” in which he starred, was unforgivably killed in rehearsals. (According to the actor’s wistful Playbill bio, “Although no one saw it, Josh was brilliant. … “)

All these pros are punching well below their weight, but how grateful we are for that.

The comedic complications to this perfect wedding are all the expected ones: cultural tensions between the bride’s Jewish family and the groom’s family of goys; the re-appearance of the bride’s unwanted ex-boyfriend; the mishap that “ruins” the bridal gown, etc. But at the end of the first act — or what would be the first act, if this overly long one-act comedy took the needed break — there’s an unexpected plot twist that promises to be a real game-changer.

But instead of leading to a sharper, wittier kind of comedy, this interesting plot development is frittered away on more inane musical numbers. Serious rescue actions are best handled by Howard, who gives a perfectly lovely, polished performance as the older sister who’s sick and tired of being treated like a jolly servant (“Jenny’s Blues”) and wants people to stop fixating on her weight and see her beauty (“Beautiful”). Boggess gets her moment late in the show with a solo ballad (“A Little Bit Less Than”) that respects her gorgeous voice, if not her intelligence.

Hargrove is also in on the rescue detail with out-of-the-blue lyric zingers that harvest their laughs from comfortable fields of corn. When the bride is having a meltdown in the ladies room, her sister hands her a pick-me-up with the inspired lyric line:  “Every bride deserves / A Vicodin for nerves.” In “Where Did I Go Wrong?” the mother of the groom enumerates all her tricks (like taking him to “everything Sondheim” to encourage any latent gay-ness) to keep her baby boy at home. And Daly’s mother of the bride teaches Harris’ mother of the groom her own secret weapon for cutting down her enemies by being “Nice.”

But let’s face it, these actors know how to get a laugh even when they don’t have a laugh line. (Grisetti cracks us up just by flashing a maniacal grin as he scoots across the stage on a scooter.) And they have a kindred spirit in Hyde Pierce, who has always gotten maximum comic mileage out of a minimalist gesture like a raised eyebrow or a side glance.

Seriously, it’s OK to laugh — although you may hate yourself in the morning.