This year's installment of Power 106 FM's annual Cali Christmas upends many of its recent traditions. The hip-hop and R&B round-table usually gets a few titans from its upper airplay ranks, some singles-toting newbies and an L.A. legend or two. But this year's lineup is a study in contrasts and shows how quickly generation gaps can emerge in the young and fast-moving Power 106 audience. Rick Ross, the rotund and resilient Miami kingpin, tops the bill with guest-verse staples Meek Mill and 2 Chainz in tow. The most exciting acts include Compton's Kendrick Lamar, whose lauded major-label debut, "good kid, m.A.A.d. city," has absolutely dominated L.A. rap. More curious is the inclusion of Toronto R&B group the Weeknd, which until now has generally shunned hip-hop and R&B showcases and festivals. Gibson Amphitheatre, 100 Universal City Plaza, Universal City. 7:30 p.m. Fri. $45-$125. Power106.com.