This most wistful of hip-hop festivals basically posits that good rappers don’t age. Thus Tribe Called Quest, the Pharcyde, De La Soul, and Mos Def can headline Rock the Bells without one good ’00s-era album among ’em. New York rap stalwarts Nas, Method Man, Redman, Raekwon, and Ghostface at least bring some fire, though there’s not necessarily so much new material there either. From a sociological perspective though, the alliances are fascinating: Hipsters (Spankrock, Cool Kids, Santogold, Amanda Blank) are apparently deemed more acceptable than, say, the LOX; meanwhile, they’re being paired on the lower half of the bill with political radicals (Immortal Technique, Dead Prez) and throwback traditionalists (Kidz in the Hall, Wale). The common thread, if there is one, is something elusive—is it that most of these guys aren’t inclined to curse much? Or maybe they all disapprove of gun violence? Whatever the link, everybody here can rap, which, come to think of it. . . .

Sun., Aug. 3, noon, 2008