Inform.vim is a project mainly written in Vim Script, it's free.
Indenting for Inform
This is a mirror of http://www.vim.org/scripts/script.php?script_id=860
Just your basic indent script. Works fairly well in most circumstances, though the odd issue still exists with multi-line conditions, and object definitions may not come out as you like them to.
Includes a rudimentary ftplugin script.