Sorry, I should have been more precise: The lack of CPAN is a fact at my place of employ, not a policy.
The scripts I write are just for myself to get my work done. The maintenance problem happens when a friend asks to use one of my scripts. I could tell them to put my personal bin directory in the front of their PATH, but my conscience compels me instead to give them a script that works without any dependencies upon my environment. Why, hello perl5.8 with no CPAN. (Now when I get laid off, my friends' scripts will still keep on working :-)
This was a request for an idiom, so I'm not that concerned about copying code and corresponding quality concerns.
That being said, there are lot of excellent answers here.