Canadian pop-punk, passive-aggressive Twitter feuds are a riot, eh? It's been three years since Avril Lavigne ripped ex-husband Deryck Whibley's heart out of his chest and filed for divorce, citing "irreconcilable differences" after three years of marriage. Lavigne is now engaged to Nickelback's Chad Kroeger. And Whibley has also moved on, dating model Ari Cooper. But Lavigne's happiness is Whibley's punch line. For Halloween, the Sum 41 frontman and his girlfriend dressed up like Avril and Chad, respectively, and then posted a picture of their cross-dressing antics on Twitter. "Hey Deryck, loved the costumes!" Kroeger tweeted in response to the photo. "We were going to dress up as you guys this year but all the parties had celebrity themes haha." He may laugh, but the joke's on Chad, because the music at his next wedding will be made up primarily of Avril Lavigne tunes and Nickelback ballads. And there's nothing rock 'n' roll about that kinda soundtrack. Meanwhile, Sum 41, like cross-dressing, is still as... More >>>