You can also mark the dependencies in your myscript.py as comments. The use case is for quick one off scripts which may require a bunch of different requirements. The integration with ipython is nice for experimenting too. I think pyenv could be useful for that use case of little one off experiments too.
One enhancement I'd like for it to also run modules or entry points like:
Setuptools entry points like used in console_scripts to work would be nice too:
fades --dependency pyenv -m pyenv.cli:cli
Or the best::
fades -m pygame.examples.aliens
So it can create a virtualenv, see that it needs the package (pygame here), and then install that package with pip, and then run the module or entry point.
Anyway... just some dreaming. Can I haz pony? All this is exciting.