“Are you really the ski patrol?” Brown, flanked by the Famous Flames, literally skis into this prime slice of ’60s youth-movie cheese and, yanking off his winter coat, makes a cabin of sweatered, smiling teenagers feel good. Ski Party, in which certified heartthrob Frankie Avalon and his right-hand man Dwayne Hickman disguise themselves as young women to get special access to their sweethearts’ social lives, was an alpine extension of the then-booming beach-party genre (famed for its heavy use of musical cameos). Brown’s performance, backed by an invisible organ and horn section, is the movie’s highlight, and another milestone besides: filming the scene, Brown later confessed, was the only time that he had gone in for a split and torn the seat of his pants.