This documentary follows the nigh-genius idea (and breathtaking financial ruin) that was a traveling Canadian music festival in the summer of 1970. Some Woodstock-era draws Janis Joplin, the Grateful Dead, the Band, the Flying Burrito Brothers, the Buddy Guy Band and others played three concerts in the course of a five-day private train ride from Toronto to Calgary. Onboard is where the real deal went down, as the bands drank and jammed nonstop. And though Festival's genial vibe and musical bliss are evenly spread, Joplin is the sinus clearer. Caught on film a mere three months before her overdose, she brings to mind a Dorothy Parker raised by bayou gypsies whether she's captured in hair-raising performance or just sitting on the train (next to a howlingly blotto Rick Danko singing "Ain't No More Cane" to Jerry Garcia's accompaniment). From the moment Joplin announces her arrival in the film with a "Cry Baby" opening wail that drives a spike right through the heart she holds you rapt under her spell.