FIRST OFF . . .

Bob Dylan joined U2 on stage Monday night at the Los Angeles Sports Arena to share lead vocals with the Irish band’s Bono Hewson on two Dylan songs: “I Shall Be Released” (which they dedicated to Amnesty International) and “Knockin’ on Heaven’s Door.” Though they didn’t join the band on stage, other rock notables in attendance over the first three nights of the band’s five-night engagement: Bruce Springsteen, Madonna, Rod Stewart, Robbie Robertson and “Little Steven” Van Zandt. U2-- subject of a cover story (“Rock’s Hottest Ticket”) in this week’s Time magazine--concludes its Sports Arena engagement tonight.