now a days i mostly script for fun... on those rare occasions when my work load isn't baring down on me... i'll find crouse in IRC and say "hey... let's work on that one project we started back in '02"
everyone once and again we (usually he) comes up with something new... and we spend countless hours working on it, and it usually ends up being a pretty robust script (encrypted bank account registry comes to mind, no the code isn't available yet

).
i've written scripts to re-encode video files (usually so i can author a dvd of my favorite anime episodes), scripts to create cd-rom backups, other small fun little non-work related things.
i can't say i really script in order to learn my machine better... i typically script to prove that i can do something that normally seems tedious and to have a means of remembering how i finally figured out something (my local script directory is pretty large, and some of the scripts in there are there just to remember syntax).