Nerve's Secret Project

During QuakeCon at the id Software press conference it was announced that Nerve Software had been selected to develop "an idea that had been percolating at id for a long time" in to a full production game. HomeLAN has an article/interview with Brandon James the co-founder of Nerve Software.

As far as Nerve’s new project, James only gave a tiny hint as to what they have in mind.We are definitely looking at facilitating team play in a cooperative enviroment. I think what we are striving for is not getting people but encouraging people to work together. "It’s not necessarily team vs. team its more like the team vs. the rest of the world".James would not comment on whether there would be an offline mode for the game

The only really known (well, not so known) game ever mentioned by id as an "idea that never happened" would be the title that was tentatively being called Quest.