As Fox's The X Factor continues its slooooow slog through its preliminary phase (we've still got 32 potential winners and live shows don't begin until next month), NBC's much more briskly paced (and, quite frankly, far more entertaining) The Sing-Off has already settled on its top ten finalists. On Monday, those remaining a cappella performers will tackle songs deemed guilty pleasures by producers, including "Jessie's Girl," "Footloose," and "I Wanna Dance With Somebody" (apparently "guilty pleasures" is a synonym for anything recorded in the eighties). Can't wait five days for your next dose of The Sing-Off? No worries: Vulture today is exclusively premiering the opening number from Monday's show, a full cast performance of Lionel Richie's All Night Long. Spoiler alert: This clip includes lots of hand gestures, faux-African accents, and at least one graphic image of air saxophone. The Sing-Off airs Mondays at 8 p.m. on NBC; the show's season finale is November 28.