We use the Plan 9 from Bell Labs operating system in several applications, as our preferred internal source control/archive, and for managing data from race shop and onboard embedded systems. We're collecting Plan 9 material here…slowly.
Right now, a mirror of videos of the talks at the most recent International Workshop on Plan 9. They were recorded and produced by Andrey Mirtchovski and Latchesar Ionkov at 9grid.net.