Before the Strokes even took the stage for their sold-out show headlining MSG, their concert took over NYC Twitter feeds with Elvis Costello's surprise opening set of "Pump It Up," "Radio Radio," and "(What's So Funny 'Bout) Peace Love And Understanding." The Garden was reportedly (i.e. retweetedly) enthralled. Given the date, those posts were helpfully tagged #notAprilsFools. And given the ...