CVS?

Can someone tell me (better yet, show me!) how to use CVS as a
repository instead of svn?

I've done the following:

set :scm, "cvs"
set :repository,  
":ext:cruisecontrol-R4HeY/0uUGeeZLLa646FqQ@xxxxxxxxxxxxxxxx:/cvs"

but it fails saying I need to specify a module to checkout!