The period between Nine Inch Nails’ 2009 “Wave Goodbye” tour and its current resurgence hardly qualifies as an extended absence. Yet Trent Reznor re-emerges as one of the few alternative-rock veterans yet to embarrass himself with subpar new material (his latest album, the mostly great Hesitation Marks, came out Sept. 3) or a cash grab celebrating the anniversary of a landmark album. But while Nine Inch Nails’ Verizon Center show on Oct. 18 promises to be a full-blown sensory experience, it’s the opening set from politically tinged post-rock ensemble Godspeed! You Black Emperor that may wind up the most surreal spectacle at the arena—outside of the Wizards’ home opener, that is.