Board Thread:Support Requests - Getting Technical/@comment-5882993-20140729181425/@comment-452-20140729191729

Some wikis, such as Community Central itself, also have a shared sandbox, usually located at Sandbox or Project:Sandbox.

"Project" is a namespace shortcut which always redirects to the namespace which shares the name of the wiki. In this case Project:Sandbox leads to Community Central:Sandbox. Sandbox also redirects to the same place, but not all wikis have that redirect.

I think shared sandboxes are useful because you can see what others have been experimenting with, and you can play with other's examples.