Time was, an artist had at least three studio albums out before releasing a live one. On his sophomore disc Tonight, Not Again--Live at the Eagle Ballroom, Jason Mraz is breaking the rules. And that’s about as bold as it gets when he brings his impeccably performed yet busily bland PBS rock to a loudly appreciative Milwaukee crowd. The accompanying DVD adds playful interviews and backstage footage to the slickly shot concert. Still, you have to wonder about Mraz’s professed road weariness when the most rockin’ thing about him is his vintage Van Halen T-shirt.