Aloha Ken,
I'm not sure what you mean by "anything else of that type", but
executing a named code block in other code blocks can be achieved with
the noweb syntax.
#+name: packages-that-make-iPython-great
#+begin_src python
import numpy as np
import foo as bar
...
#+end_src
#+header: :noweb yes
I'd like to have some language specific code (either a code block in the
Library of Babel, in the current file, embedded in elisp in my startup
file, wherever) run each time I execute any code block. Is there a way
to specify this via header arguments, or :prologue, or anything else of
that type?