There is more Mel Brooks than Thornton Wilder to Forum, though, with its kibitzing plot built on Pseudolus’s attempt to earn his freedom by setting up his young master, Hero, with Philia, the courtesan next door. This requires some doing, since the valuable virgin has already been purchased by the mighty Miles Gloriosus and is coveted by the blushing lad’s dad, the henpecked Senex. Throw in the classical trimmings attached to neighbor Erronius and a desperate bit of cross-dressing by “slave in chief” Hysterium and you’ve got buffoonery that stretches across the ages.

Devine slims the cast to 15, which includes the trio of “Proteans” who serve as slaves, eunuchs, and kazoo-blowing soldiers. Marcus Lycus fields less fleshly merchandise than is customary and caters to more diverse tastes, offering a boy-girl set of Gemini. The togas are accessorized with sneakers and work boots, not to mention a necktie for Senex and leopard platforms for Lycus. The mostly non-Equity cast sings nicely, especially Christopher Lyons as a bristle-headed kid of a Hero, Jennifer Ellis as the happily airheaded Philia, and Shannon Mühs as a refreshingly un-battle-ax-like Domina. But it falls to the pros to pull off the oft-hoary comedy. Bill Gardiner is more schlubby than wily as Pseudolus, but he can draw inspiration out of his boxers when he needs to. Richard McElvain brings a droll combination of resignation and last-stand lechery to Senex. And Neil A. Casey, with his gift for acid agitation, was born to play Hysterium.

AMERICAN BUFFALO is the expletive-happy poetry that leaked from the pen of David Mamet as he was turning 30, in 1977, with an ear pressed to the shabbier streets of Chicago. The rhythms he recorded, heightening them into a rambling mix of profanity, anthropology, and all-American entrepreneurialism, were Caucasian, but they don’t suffer from a little African-American cadence being mixed in. Neither is director Evan Bergman — whose all-black production is currently sharing Wellfleet Harbor Actors Theater’s Julie Harris Stage with an impressive jumble of detritus (through October 14) — the first to put Mamet’s symphony of convoluted tough talk and botched syntax into African-American mouths. Teach, the most flamboyant of the play’s three small-time crooks, has been famously assayed by white actors Robert Duvall, Al Pacino, and Dustin Hoffman. But Michael Corrente’s 1996 film deployed an African-American, Sean Nelson, as Bobby, the young, possibly recovering druggie huddled under the wing of junkshop proprietor Donny as the play’s trio, bungling a coin heist as well as their relations, demonstrate the pathetic ruthlessness of American business.

The WHAT production, then, is solid if not revolutionary, with Reg E. Cathey a tense rather than showy Teach, the danger in him tightly coiled even as the surface umbrage leaks out all over the place. Hubert Point-Du Jour is a shifty but childlike Bobby and Paul Butler a stolid, commanding, if soft-spoken Donny. And the play, hilarious and heartbreaking whatever color you paint it, remains a bristling testament to Mamet’s stage genius as yet unburdened by theory or affectation.