This opens up the door to a few novelty ideas too.. each submitter could submit a block of (pre-tested) code, and the site could execute it to ensure that a pre-defined list of inputs match the pre-determined set of outputs. The site could profile each person's submission (via Benchmark or something) and people would vote on their favorites (most elegant, most readable, most obfuscated, etc.) along with the system-chosen fastest and/or most CPU-friendly.
Even if it isn't used as a supplement to site experience, it would still be pretty fun. Maybe we need a more flexible XP system ("medals") that would be awarded to people for exceptional posts or as they win categories.
In this example, the trick would be doing it securely. Safe.pm is pretty safe, but only if you eliminate quite a few useful opcodes (e.g. eval and sprintf). Maybe "Safe" versions of these can be written in Perl.