Mathematica may have pioneered the notebook[X], but there are imitations[1] which are arguably just as good (or better given the seeming ad-hoc nature of the Mathematica language).
[X] I don't presume to know -- it's just the first system I came into contact with which has this concept.
[X] I don't presume to know -- it's just the first system I came into contact with which has this concept.
[1] http://ipython.org/
(edit: apparently there's some magic markup I don't yet understand.)