Inspired by the cult-acts thread.

What's interesting to me is when I go into 24 Hour Fitness, or some such, I hear Siouxsie & the Banshees. Heck, Siouxsie barely made 80s alternative radio stations back in the day, and now you can do stomach crunches to "Spellbound".

Predict what bands, and what songs in particular, get massaged into the mainstream 20 years from now.