Kevin Lenzo is:

• the active maintainer of the CMU EFnet IRC server,
• the author and maintainer of the INSANELY cool infobot project (http://www.infobot.org/),
• and most importantly, the unpaid organizer of the non-profit Yet Another Perl Conference (http://www.cs.cmu.edu/~lenzo/yapc/), a grass-roots open-source conference that turned out far better than O'Reilly's $1,000-per-person corporate-oriented Perl conference.

Sure, this isn't the kind of visibly heroic evangelistic effort that you see from people like RMS and ESR and Bruce Perens... but then, if you're looking for unsung heroes, I couldn't think of a guy who deserves it more.