deplate converts wiki-like markup to LaTeX (standard classes, koma, dramatist, sweave), HTML/PHP (single page, chunked/website, HTML, or s5-based slideshow), DocBook (article, book, man/ref page), and really plain text. Currently supported input formats are viki and Ruby's rdoc. The viki markup supports footnotes, citations, index, table of contents, embedded LaTeX for mathematics, integration with R for dynamically generated figures and tables, and more. Output can be customized via page templates.
Texpipeline allows the conversion of (La)TeX documents with simple filter pipes such as "cat input.tex | tex2pdf > output.pdf". It removes the hassle of running (la)tex again and again, leaving lots of auxiliary files in the current directory. This is especially useful for programs which create LaTeX files automatically and just want to present the PDF output to the user.
IDX-DocBook2LaTeX is a stylesheet which translates DocBook documents into LaTeX. It is written in Perl, using the XML::XPathScript package from AxKit. It features the ability to handle tables, indices, figures, footnotes, and more. The XSLT-like templating philosophy built into XPathScript makes it easy to extend.
WP2LaTeX is a program designed to translate WordPerfect documents into LaTeX 2.09 and LaTeX 2.0e. It is able to cope with Macintosh WordPerfect 1.x, 2.x, 3.x, and 4.x and PC WP 4.x, 5.x, and 6.x documents (WP 7.x and 8.x have same binary file format as 6.x, so no additional conversion module is necessary.)