A slender man (Taylor Mac) arrives on stage in a lifeboat; his sturdy peer (Mandy Patinkin) climbs out of a trunk. Strangers, they alone have survived a great flood. And for the next 90 minutes, the pair explore the realms of human existence, seeking to commune and thrive, despite the enveloping bleakness—purely through song and dance. The result is The Last Two People on Earth: An Apocalyptic Vaudeville. Viewers are given plenty to ponder, even as they giggle. Roles intertwine: sometimes Mac is the clown, or “Lear’s fool,” as Patinkin said in an A.R.T. interview. “But at times he’s Lear and I’m the fool. That’s what’s really fun about the relationship.” The intimate project was directed and choreographed by Susan Stroman, a veteran of big Broadway musicals, and debuted in 2013 in workshop form in lower Manhattan. Mac is a playwright, songwriter, and cabaret and drag performer—among the edgiest actors working today. He and the equally versatile stage and screen actor Patinkin are clearly kindred spirits. Their singing voices meld perfectly even as they exploit a yin/yang physical dynamic. A fluid, elastic presence, Mac can also beam beatifically. Patinkin, with his meaty forearms is, at least initially, more of a reluctant rock. But he comes around. Who wouldn’t—when stranded with Mac and roused by a musical lineup from children’s ditties and Rodgers and Hammerstein to Gillian Welch, and, naturally, R.E.M.’s take on cultural chaos and new beginnings: “It’s the End of the World as We Know It (And I Feel Fine).”Do you?