It must be Norway's longest festival, and happen in Oslo 1 – 19 October, when they have ULTIMA - Oslo Contemporary Music Festival. Programme to download in PDF here.
I would have checked out Alter Ego with works by Deathprod and Biosphere in the church "Kulturkirken Jakob" (11 October), and Frode Gjerstad and Peter Brötzmann with Nordic Voices the same place 16 October. Farmers Market play 13 October and how about Arne Nordheim’s sound installation in the Bekkelaget sewer cleaning system? Shit!