Vim-Syntax-File-for-Google-Code-Wiki is a project mainly written in Vim Script, it's free.
Vim Syntax File for Google Code Wiki
This is a mirror of http://www.vim.org/scripts/script.php?script_id=3173
This is a syntax file for Google Code Wiki, supporting highlighting of main features of Google Code Wiki, like:
Besides syntax and folding features, it has a powerful function for the formatexpr option. Just :set formatexpr=googlecodewiki#FormatExpr() and you will be able to format your texts without breaking link blocks or quote blocks. This features can be turned off with global variables.
You might want to follow its development on its Google Code page: http://code.google.com/p/vimgcwsyntax/