Good idea, I really like examples that actually work.  The particular file in question is part of the test suite.  Do test files always get installed from the tarball installation?  If so it's easy to put in the path relative to `ascii.__path__`.  In my current environment which I pip installed, the test files are in the astropy installation.

One minor concern is making sure the sample output isn't so long as to reduce the signal-to-noise in the docstring.