Now this takes narrowcasting to an absurd new height: a worldwide music festival where speakers are replaced by headphones:
Plug, held here Saturday, is just what you'd expect from a music fest: rotating performances in front of a live audience, socializing and plenty of beer. But the headphones (bring your own) replace a traditional concert's amplified speakers, and much of the socializing happens over a computer terminal linked to an IRC chat room, populated by members of the global audience listening to the performances over the internet. (from wirednews)
It's not the geekiest thing I've ever heard of, but it's pretty close.