THEATER REVIEW:

Nearly 50 years ago, a young lyricist with a pair of Broadway hits (“West Side Story,” “Gypsy”) behind him decided he wanted to go the whole nine yards in musical theater — compose the music as well as write the words.

His initial effort — the first of many in a Hall of Fame career — was “A Funny Thing Happened on the Way to the Forum,” and Stephen Sondheim was off and running.

With a book borrowed liberally from ancient Roman comedies, scripters Burt Shevelove and Larry Gelbart aligned with Sondheim to produce one of Broadway’s funniest musicals, one that continues to tickle the ribs of today’s audiences. The latest incarnation currently is on view at the Costa Mesa Civic Playhouse.

The structure of “Forum” invites, and almost demands, directorial ingenuity — and Costa Mesa’s Stephen Reifenstein is well up to the task, staging new gimmicks and updating some snippets of dialogue to get a rise out of playgoers who may have seen the show on numerous occasions. One game show segment drags somewhat, but most of the new stuff works quite well.

Reifenstein, in collaboration with musical director Erik Przytulski and choreographer Edward Bangasser, has mounted a sprightly, energetic version of this comical old-timer that maneuvers through some rough spots but emerges happily triumphant.

The actors often appear to be ad libbing at moments that, in all probability, are finely tuned (an exception being an incident opening night in which a tossed scroll landed unexpectedly on a high beam instead of in the recipient’s hands).

Heading the cast in this Roman romp is the slave Pseudolus, who manufactures a complicated scenario in an effort to please his master and thus gain his freedom. Scott Borden — a far cry from the middle-aged, overweight actors who normally assume the role — uses his youth and dexterity to propel the show’s myriad twists and turns in a totally pleasing performance with his slippery demeanor and frequent asides to the audience.

The funniest portrayal of the evening, however, is Brian Drummy’s hysterical Hysterium, the “slave in chief” who becomes the butt of a number of physical gags, the best one centered on Drummy’s sequence in drag, impersonating a deceased bride in full white gown and veil.

Luke Yellin is effective as their young master, a lovesick fellow with designs on the virginal and vacuous courtesan next door — winningly enacted by Megan Burns.

Their duets on “Lovely” and “That’ll Show Him” are beautifully presented.

Peter Westenhofer scores as Yellin’s sly and frisky father, while Clare V. Solly lacks only the horned helmet in her Valkyrie-esque turn as his domineering wife. David Chorley is a hoot as the flouncing flesh purveyor Lycus, and Rick Hardgrove is appropriately dizzying as an elderly neighbor, Erronius, scouring the scene for his long-missing children.

Among the supporting players, none stands taller — figuratively or literally — than Jeff Calof as the Roman warrior Miles Gloriosus. Calof’s deep, booming voice projects ultimate authority, and his presence reduces those around him significantly.

The “girls next door” — courtesans up for sale to the highest bidder — are beautifully portrayed by Laura Pasarow, Jennifer Harmon, Jennelle Wax, Nikki Martensen, Simone McAlonen and Melisa Cole. All excel in sultry salesmanship, with Pasarow offering the most pleasing performance.

The backbone of any production of “Forum” is its Proteans — “three men (or two men and a woman in this case) who do the work of 30,” to quote Pseudolus. Travis Ammann, Bryan Seastrom and Mary Wilson comprise the industrious triumvirate, and their antics are particularly uproarious.

Both the immaculate setting and its illumination are well-created by Jon Hyrkas, while Megan Endicott-Morrow has a hand in the show’s inventive choreography.

Stephen Sondheim may be America’s most sophisticated Broadway composer today, but it’s always a kick to turn back the clock and enjoy the sheer unbridled madness of “A Funny Thing Happened on the Way to the Forum.”

In Costa Mesa, the formula still packs a punch.

Michael Dale Brown, one of the stalwarts at the Costa Mesa Civic Playhouse, has written a stage satire of monster movies from the 1950s. Called “Earthlings Beware,” it opens next Friday at the Found Theater in Long Beach.

Reservations and further information are available at (562) 436-7676.