Mercurial engenders an easy distributed working style. But, for important projects you might like to have a central repository that everyone pushes to and is backed up regularly. Since this central repository is backed up, it is irritating to have a working copy of files in it (which is the default behavior of Mercurial).
To have a central repository with no working copy, clone your existing central repository using the
$ hg clone -U FoobarCentralRep FoobarNewRep
Let everyone working on projects clone from this new repository and push their changes back to it:
$ hg clone FoobarNewRep MyFoobarExperiments