I, of course, am a big fan of jokes -- large-scale, bombastic ones that anger fans of adult contemporary music and incite local Swedish goons to twisted threats of physical retribution. But what follows is no joke: Nas' show on April 25 at Racks will not be taking place. First thing's first. Everyone that has purchased a "door pass" for the April 25 "Hip Hop Party" at Racks, featuring Nas will be fully refunded.