Everyone knows that any good performance hall worth its salt is haunted by ghosts. The NAC is no different. If you roam backstage, (and you're really, really quiet) you might hear an otherwordly voice reciting a line from Shakespeare's King Lear, or Michel Tremblay's Les Belles-soeurs. Or you might glimpse a vision of an ethereal prima ballerina, desperately racing toward her cue on the Southam Hall stage. The NAC's specters are (mostly) friendly, with names such as Oscar, Glenn and... Hamilton. This Sunday, September 30, from noon to 4 p.m., amateur ghost hunters can come to the NAC for a 45-minute self-guided backstage tour as part of Culture Days. They can poke at the theatre curtains or, carefully, peak behind the dressing room doors, perhaps to catch the silhouette of a Rudolf Nureyev or Victor Borges. They can close their eyes and let Bach's Goldberg Variations transcend their being to float up into the imposing hexagonal space above. If ghosts aren't your thing, check out the tango and hip hop dance workshops, the photography exhibits, the choir rehearsal or the theatre and poetry workshops. They're all part of Culture Days at the NAC.