Sometimes we dance like there's nobody watching. And sometimes we dance knowing full well that everyone is watching, but we don't care.

Marva Smalls onstage with an Alvin Ailey dancer. Getty Images

Wednesday night's opening of the 2012 season of Alvin Ailey American Theater began with one man onstage, dancing on his own as the audience filed into their seats at City Center. He was joined by several other members of the company, all dressed androgynously in black suits, as the lights went down.

About halfway through the piece, "Minus 16," the troupe stepped down from the stage and into the orchestra, each performer extending a hand as an invitation to dance with unknowing audience members.

Mo'Nique Getty Images

Ginger Crosby kicked off her shoes as soon as she got onstage and threw her hands in the air. ("I would have worn sensible shoes if I'd known," the septuagenarian said later, at the opening gala at the Hilton.) A svelte audience member in a hot pink cut-out gown and a mink stole kept pace with her lithe partner, despite her five-inch stilettos, and a rotund brunette took center stage with her bold moves, reminiscent of Ricki Lake in the movie "Hairspray."

One dapper fellow looked a little unaccustomed to having to follow, and the whole group looked bemused, if slightly bewildered, as they were led around the stage. As they filtered back to their seats—after finding their shoes—one woman in a silver-sequined top remained in a swaying embrace with an Ailey dancer. The rest of the troupe fell away, leaving the two sparkling together onstage.

That is, until the entire company fell on the floor, lying flat while the audience—which included Judith Jamison, Ailey's artistic director emerita, and chef Marcus Samuelsson—roared for the only one still standing, Marva Smalls. She offered a hand to her partner, then exited in the spotlight.

"When I saw them coming down the aisles, despite the glitter top, I tried to sink down in my seat," Ms. Smalls, who works at Viacom, said afterward at the gala. "But once you're up there, you lose all sense of everything but the dancer you're with. I had no idea I was the last one onstage."

Mo'Nique, the evening's honorary chairwoman, noticed, and called out Ms. Smalls before commenting on the $2.4 million raised for the company that evening. "To the woman in the silver top and black skirt: I got his number. His name is Charles and he's a Sagittarius."