Partial clone/pull?

I have a local git repository of a server project that I'd like to distribute. However, I don't want to distribute EVERY file in the repository, but I *would* like to distribute the full set of changes for those files I do plan to release.

I'm having some trouble figuring out how to do this. I assumed I'd create a new repository and then use git pull to merge the directories I want in my distribution repository. I can't seem to find a way to specify what files I want though.

Let's say I had a repository called stuff, with directories a, b, and c. I want to make a distribution repository containing just a and b, but with full histories so a "git pull" will sync from the stuff repository, but ignore the "c" directory.

Any suggestions?

Thanks!