If someone else has begun a project, and you want to check out a playpen version of it, all you should need to do is check the project out of the CVS repository and then run ./autogen.sh in the top directory of the project.
If you don't have access to the same package archive the original author was using, try making a etc/package-archives.local file that contains URLs for package archives you wish to use. You can list several URLs in a etc/package-archives; If identically-numbered versions of a package are are available at more than one listed package archive, the package from the first archive will be used.