Text::Textile is a Perl module for converting Textile syntax to XHTML.
From Wikipedia:
Textile is a lightweight markup language originally developed by Dean Allen
and billed as a "humane Web text generator". Textile converts its marked-up
text input to valid, well-formed XHTML and also inserts character entity
references for apostrophes, opening and closing single and double quotation
marks, ellipses and em dashes.