Orion's Arm: CC-licensed, post-Singularity shared world

Orion's Arm is a Creative Commons-licensed hard sf/post-Singularity shared world where lots of fan writers are collaborating to build a world and then write stories in it. There also seems to be some RPG adaptation activity and illustration. The storyline is a pretty thoroughgoing post-Singularity thinggum with lots of opportunity for fun noodling.
Our goal is to create a dramatic far-future universe that is internally consistent and abides as much as possible with the accepted facts and theories in the physical, biological, and social sciences. Thus matter cannot travel faster than light, matter and energy are conserved, no evolved humanoid aliens have been discovered, future ultratech social issues are likely to be very different to those of today, and so on. We embrace speculative ideas like drexlerian assemblers, mind uploads, posthuman intelligences, femtotech, magnetic monopoles, wormholes, as it is proposed that future sciences, technologies, and developments will make these possible. And we attempt a logical explanation for even the most fantastic-seeming elements in OA. We aim to paint a future that is plausible at every level, from the scientific to the social to the psychological...

Somewhere between the years 2020 and 2050 researchers would develop the technology of Direct Neural Interface, allowing human minds to link with their computers. They would advance genetic engineering to the point of the first optional improvements or ‘tweaks’ to the human genome as well as create the first ‘provolved’ animals engineered for human level intelligence. The dream of nanotechnology would start to be realized, as nano-scale manufacture became a viable industry. And, using a combination of nanotech created advanced materials, robotics, and tele-operated devices, development of a truly viable and self-sustaining space infrastructure began in earnest. Finally, and perhaps most importantly, in the year 2040 researchers created the first human equivalent, or turinggrade, artificial intelligence. The future would never be the same again.

Link (Thanks, Derek!)