Studio Dante is a place that allows actors to let it rip, and Jordan Gelber and Thomas Sadoski are making the most of their opportunity in "The Joke," a tasty two-hander by Sam Marks.

They play a comedy team working the Catskills in the 1960s and '70s, getting few laughs while undergoing all the stresses of a doomed marriage. Mr. Sadoski is Ed, the slick half of the pair, and the stout Mr. Gelber is Doug, who when the play opens in 1965 is mostly there to be the object of Ed's fat jokes.

Mr. Marks, though, has studied his Lenny Bruce: Doug undergoes a transformation, taking over the spotlight with a new type of material that doesn't try to be humorous. And just as in a marriage in which one half of the couple changes while the other stays the same, the relationship deteriorates. Allusions to a woman and to the historical context as the '60s give way to the '70s are tantalizing but not overdone; the focus stays on the two men.

Mr. Sadoski and Mr. Gelber play it beautifully under Sam Gold's direction, going from performance mode on the make-believe Catskills stage one minute to arguing behind the scenes the next. If their comic routine doesn't really seem credible ??? aren't duos supposed to interact onstage, like Rowan and Martin? ??? their growing tension is perfectly believable. And, reminiscent of the third-tier acts in the real Catskills, their jokes generally stink.