Sedsed is a Python script that masters sed scripts. It generates sed debug files in sed, which lets you debug scripts with your own version of sed (Linux, DOS, etc.). It's also a script beautifier, doing indentation and spaces/comments formatting. It can also convert sed scripts to colorful HTML files.
Txt2tags converts a text file with minimal markup to HTML, XHTML, SGML, DocBook, LaTeX, Lout, Man page, Creole, Wikipedia, Google Code Wiki, PmWiki, DokuWiki, MoinMoin, MagicPoint, PageMaker, AsciiDoc, or ASCII Art. It is simple and fast and features automatic TOC, macros, filters, include, tools, GUI, CLI, and Web interfaces, translations, and extensive documentation.
^txt2regex$ is a Regular Expression "wizard", written with bash2 builtins, that converts human sentences to regular expressions. With a simple interface, you just answer questions and build your own regexp for a large variety of programs, such as awk, ed, emacs, grep, Perl, PHP, procmail, Python, sed, and vim (there are more than 20 supported programs). As it is written in bash, no compilation is required.