Green Day's longevity and penchant for reinvention shouldn't come as a surprise. After all, the band had almost an entire career as long-haired, DIY pop-punkers in the late '80s and early '90s, releasing two albums on the indie Lookout Records and inspiring hordes of imitators before leaping into pop-culture consciousness with its major-label introduction from 1994, Dookie (a fact a recent AP article completely failed to realize when it erroneously cited Dookie as the group's debut album). And yet when Green Day staged its comeback in 2004 with the Grammy-winning concept album American Idiot, it did indeed feel like a shock. Granted, even back in the Lookout days, Green Day had broader pop ambitions — but American Idiot showed just how much craft and passion was left in the band's pop-punk grab bag. While the group's new 21st Century Breakdown feels like a revisiting of Idiot's themes and sound, there's no denying the punch and timelessness of the disc's debut single, "Know Your Enemy."