The idea that rock is exclusively a young man's game hasn't held water for three decades. While there's still something off-putting about Mick Jagger's determined athleticism in the service of a catalog that's older than Justin Timberlake, there's no denying he can still fill football stadiums, and not just with boomers.

Hip-hop is another matter, and the big story this year was the comeback of Jay-Z less than three years after he quit at the top of his game to become the CEO of Def Jam Records. Though bragging that your skills are better than the next MC's is as central to rapping as high-end athletic footwear, Jay-Z was arguably the best, both commercially and critically, and his retirement was an implicit acknowledgment that he was getting too old for the mic.

Unsurprisingly, his comeback album "Kingdom Come" was met with snickers. It's not a bad record, but it dwells self-consciously on age ("30 is the new 20") and the corporate life. Money, of course, is a prerogative of gangsta rap, and Jay-Z wants us to believe that taking conference calls on the beach is as hard and real as taking out rival drug dealers.