"It Might Get Loud" is an epic, exhilarating backstage pass into the world of some of the biggest guitar rock stars around. Over the course of one day, three generations of electric guitar phenoms come together, crank up their amps, and let it roll. Documentarian Davis Guggenheim gives us so much more than an all-star jam session; he leads us to these artists' inner sanctums and illuminates the paths each one traveled to forge a sound of his own. Jimmy Page ("Led Zeppelin"), the Edge ("U2"), and Jack White ("The White Stripes") seem genuinely to enjoy each other's company while sharing riffs, swapping stories, and divulging their distinct philosophies of craft. "It Might Get Loud" does get loud, and in the process, opens up our minds and hearts to a whole new way of listening to and enjoying what it means to rock.