Joke supergroup features members of Mumford & Sons, Vaccines, Old Crow Medicine Show
Band recreates atmosphere of famed 1969 shows in stage set
U.K. fest roars back with memorable sets after a year off
Folk-rockers joined by Vampire Weekend, Vaccines during headlining set
Lineup includes Wilco, Wu-Tang Clan, R. Kelly, Bjork, more
'Great records are not perfect - they're human,' says frontman Justin Young
U.K. rockers plan collaboration with the Strokes' Albert Hammond Jr.
U.K. band peforms 'If You Wanna'
Foo Fighters, Deadmau5, Cage the Elephant, My Morning Jacket, Eminem, Lykke Li, Coldplay, Muse, Bright Eyes and more from Chicago