So Mac OSX has the
say command, which reads out some text in the computers voice synthesis functionality. This is old news.
The new hotness is switching into the "cello" voice with
say -v cello. I's lyrical and beautiful, though reading out file names is entertaining:
say -v cello source/_posts/2013-08-24-cello-voice.markdown
This was brought to my attention through the
guard-shell gem README.