OSGrid is the primary grid used by members of the OpenSim community for development, testing, sharing content and social events. It allows those with servers to add on regions very easily and without cost. OSGrid runs entirely with volunteer effort and relies on donations from the community to meet the fees for its servers and other costs. Avatars can be created on OSGrid at no cost via http://osgrid.org. OSGrid supports the HyperGrid meaning that avatars can visit and travel to and from OSGrid from other OpenSim grids such as our main Openvue grid.
The Virtual University of Edinburgh (Vue) has several test and experimental regions mounted on servers in Edinburgh that are connected to OSGrid.