MCNP syntax highlighting in vim

This syntax highlighter for MCNP in VIM is due to Giacomo Grasso. The file on his page is inaccessible other than through the white paper, so I have taken the liberty of extracting it and putting into a file available for download. Put it inside the ~/.vim/syntax folder.

There's no easy sure-fire way of detecting an MCNP input file, but if you create a file at ~/.vim/scripts.vim with the contents

if did_filetype() " filetype already set..
  finish  " ..don't do these checks
endif
if getline(2) =~ '^C.*\<mcnp\>\c'
  setfiletype imcnp
endif

it will load the MCNP syntax coloring if the second line of your input deck is a comment (the first letter of the line is a 'c') with the word MCNP in it somewhere.