These are very useful when you play Perl Golf, and can be pretty powerful in the hands of an expert player (sadly, my dreams of becoming one has remained just that.)

The author of this document was a regular in Perl Golf tournaments and also in the Fun With Perl mailing list, which was a precursor and launchpad for several of these tournaments.

For those interested, here is a series of articles about "The Lighter Side of Perl Culture": http://www.perlmonks.org/?node_id=410774

See also, "Perlgolf History" at http://terje2.frox25.no-ip.org/perlgolf_history_070109.pdf (not sure if this link is still alive.)