Ever wonder what it might be like to live on a doughnut-shaped world? NASA has created a Web page that gives you a sense of what life would be like in a ringlike structure out in space, where there is no gravity except the centrifugal force generated by the structure’s spin. Simulation requires a Java-enabled browser.

Go to: http://www.nas.nasa.gov/About/Education/
SpaceSettlement/teacher/materials/ringworld/