A Simple Theatre’s Congratulations, Joe isn’t really much more than a two-hour sitcom, but thanks to Ricky Wayne and Meg Heimstead, it offers some of the most hilarious moments of this or any theater year.

Consider, for a moment, Ricky Wayne. Anyone who’s watched this talented actor do improv Sunday nights at American Stage knows that he loves extreme attitudes, and can go from zero to devastation-at-the-top-of-his-lungs in under three seconds.

Well, Joe gives him the opportunity to do that and much more, and I for one want to start laughing just from the memory. Imagine a nervous, desperate, neurotic, chattering, panicky, intimidating loser with a hustler’s instincts, and you begin to have an idea of the spectacle his character (whose first name happens to be Wayne) makes. He’s also a substance abuser, hopped-up on Pepto-Bismol when he’s not snorting Pledge, and when his colitis has him farting, he sprays enough air freshener to cover the whole stage in smog.

Can anyone really take a romantic interest in this train wreck? Yes, and that someone is Meg Heimstead as Darlene. Heimstead so often has played ultra-serious roles in the Bay area, it’s a joy to discover that she’s also a gifted comic. Her Darlene is one of the Really Crude Housewives of New Jersey, terminally vulgar and demanding and loud, anxiously devoted to her obnoxious lover, and spitting out heavily accented exclamations while she chews gum and the scenery. When these two performers are on stage — and I’m happy to report that they often are — Congratulations, Joe is a clinic on shameless, fearless, priceless histrionics. You say the play, however, is meaningless? Well, you’re right, but in Wayne and Heimstead, it justifies its existence. No circus clowns were ever funnier.

But let’s talk about the vessel that tries to contain these two talents. Joe is written by Lee Irby, a novelist and history professor at Eckerd College, and it offers likable dialogue in the service of the thinnest of plots. Its central subject is Joe (Sam Arnold), an overage schnook who still lives with his parents and only applies for jobs so that his unemployment checks will keep coming. To everyone’s (including his own) surprise, he gets a job at the local prison, and this leads to a new girlfriend and a couple of promotions. But Joe never really takes control of his life; he’s dominated by his new paramour, recruited by his aunt’s hapless lover (Wayne) and just as muddled with a paycheck as he is without one. There’s a little more — mostly some parties to celebrate his progress — but that’s pretty much the whole story. Don’t look for suspense or astonishing twists.

But if you look for acting, you’ll find much to enjoy. Best of all besides Wayne and Heimstead is Kendall McGuire as Julia, the girlfriend who compensates for the chaos of her childhood with cold, humorless rigidity. Julia is a feeling person’s nightmare, all about control and precision, and McGuire plays her as the exact opposite of mile-a-minute, skittish Wayne. As Joe’s mother Helene, Bonnie Agan turns in a fine performance, though the play doesn’t ask much more of her than that she be loving and supportive.

In the title role, Sam Arnold is just too paradoxical: He does a top job of appearing desperately incapable of any sort of competence, but then how are we to account for his promotions at work or his attractiveness to Julia? (This is probably a script problem, but it’s one that the actor and director need to solve.) Finally, Eddie McNally as Joe’s father Dominic is tolerable without distinguishing himself — one can’t help but wish that he and his stage wife were as extreme as the other characters with whom they interact.

Jerid Fox’s living room set starts out well enough, with its helium balloons and giant greeting card — but why doesn’t it change much when supposedly weeks have passed? Jessica Thonen’s costumes are terrific, though, from Joe’s nondescript togs to Darlene’s ostentatious get-ups. Gavin Hawk’s direction is at its best when the onstage action is most frenzied — I’m so grateful he had the confidence to let Wayne and Heimstead go wild.

And wild is just what this show is at its best. Congratulations, Joe may feel like a network comedy much of the time, but when Wayne and Heimstead are let loose, all invidious comparisons vanish and we’re in the presence of pure pleasure. With their sure sense of the ridiculous, they’re the reason to be there. If you need a laugh — and who doesn’t? — don’t miss them.