The first thing that I did with Perl which resulted in my
learning a lot of it was I wrote a program that was an
endless loop. Every time it read a line it would copy the
clipboard into $_, do something, and copy $_ back to the
clipboard. (Using Win32::Clipboard of course.)
The "do something" could be standard reformatting, copy,
run some code, whatever. The script was awful in design and
execution. However by always reaching for this (while
working in VB without a decent editor) I learned regular
expressions, had somewhere to play around with snippets of
code meaning that I learned more, and it helped me get
work done.
In fact I still use the darned thing...