[jedbrown]

    $ git bundle create one-file.git --all

That creates a single file containing all branches in the repository. It's a plain file so you can copy that around with any protocol you like. Open it with

    $ git clone one-file.git new-repo

If you want to collaborate on further development and don't mind running something on the server, gitolite [1] is stable and powerful. Note that if your repo becomes popular, _you_ might be served with the takedown notice.

[1] http://gitolite.com/