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.