It's that magical time of year once again, where the entire nation leaves the house looking ridiculous on purpose! Yay! Occasionally, Halloween costumes based on musicians border on genius -- like Sum 41's Deryck Whibley and his girlfriend Ari Cooper hitting a party a few days ago dressed like Deryck's ex-wife, Avril Lavigne and her new fiance, the ever-hateable Nickelback frontman Chad Kroeger. Ballsy, hilarious and quite the statement, we applaud this wholeheartedly. Sadly though, dressing up like most musicians is usually incredibly boring and obvious. Here are some singers you absolutely, positively, should not even think about dressing up as for that party tonight.