Ringworld

Stuck for inspiration so I took an old marble and a 9.5cm steel ring I bought for an odd job at home and made a mini earth with a dyson ring or ringworld around it. 
Stop reading now as the rest should be on the Dull Mens Club on FB!

I then wasted far too much time working out that if the marble was the earth then this ring would have an orbital diameter of about 161,000 km and a ring thickness of  6000 km. To get 1g spin gravity then it would have to rotate once every 5 hours which would be 100,000 kmh. A bit fast so if I give it 1/6 moon gravity then it would be 17,000 kmh which is less than the space station so that's fine. But I think we may need at least 0.4g to survive long term.
The surface area you could use to live on,  say the third of the circumference with the gravity would be over 3 billion square km which is 6 times the surface of the earth.

Let's build that for the next 1000 years instead of killing each other.