Atavism [ˈætəˌvɪzəm] The appearance of characteristics that are presumed to have been present in some remote ancestor;reversion to an earlier biological type.“
Starting these kind of text with a dictonary entry is probably not very creative. On the other hand, this word sounds too made up to trust your ability to google it. The rest of the work is finding a possible analogy to music and nightlife. That is up to you. For us it is about techno and these special nights, where you get in a certain mood and it's not just about hooking up, beeing cool or getting high anymore. Weird as it is, this is the stuff that let's you keep going out. Atavism is a certain niche for upcoming artists and locals to present their music in an otherwise oversatturated and more and more exploited city.