SAN FRANCISCO — A half century ago, when MC5 (the Motor City Five) burst onto the scene, America was in crisis. Ideological differences were tearing the nation apart. Racism was everywhere. Cities were on fire. Tribal…

Good news! We’ve made it to the ’90s in RIFF Rewind. OK, yeah, it’s still technically 1989. But any list that includes Nirvana, Nine Inch Nails and Faith No More’s “Epic” is basically the ’90s,…