As with many of Steve Dahl’s greatest stunts, his infamous Disco Demolition Night started as a joke. When WDAI-FM (94.7) – now known as WLS-FM – changed format from rock to disco, DJ Dahl was out of a job. “That’s where it really started,” said Dahl, 40. “While I was still on (WDAI), I would be talking about how ridiculous it was to have a 24-hour disco station. Like who’s going to dance to a 20-minute Donna Summer song in the car? Back then, disco was more of a cultural thing than it is today. It seemed like (disco) was trying to take the place of rock ‘n’ roll, which is why I found it kind of irritating.”