Oh, yeah, I was disappointed that they didn't have Aztec, Mayan, or Incan dates. That's why I'll write one, if for no other reason.

You can have Mayan dates in CPAN (and Discordian and Hobbit, too). On 2003-02-03, my .profile script will print:

Today is Quintidi 15 Pluviôse CCXI, jour de la vache
Hebrew: 5763 Adar 1
Maya: long 12.19.9.17.9, Tzolkin 7 Muluc, Haab 2 Pax
Prickle Prickle, Chaos 34 YOLD 3169
Today is Mersday 12 Solmath 7467

Thanks to: http://search.cpan.org/author/ABIGAIL/Date_Maya-1.1/
http://search.cpan.org/author/RBOW/Date-Discordian-1.35/
http://search.cpan.org/author/TBRAUN/Date-Tolkien-Shire-1.1/
and others