It seems like reading the book is different from hearing the talk then - I saw the "Perl Hacks" talk at YAPC::E and wasn't really impressed by the recommendation of P5NCI or the vi tricks - can you maybe tell us a trick that worked for you?

There is Contribute a hack to the new "Perl Hacks" book and there is Perl Hacks: Rough Cuts Version (which doesn't link to relevant information anymore), but I'd like to hear concrete examples unless they give away far too much of the story. You could put them in spoiler tags maybe ;-).