Using Mercurial: The pull-only model
Instead of using a central repository, Mercurial can be used without ever
calling push.  The pull-only model works as follows:
-  Every team member has a private repository.
 -  When a team member wishes to distribute changes, there are two options:
  
  -  Create a zip file of the contents. Then email the other team members with the zip file.
  
 -  Place the files on a USB drive.
  
 
 -  Each team member then executes 
hg pull (with the location
     of the source repository as a parameter) to update their own repositories.