I have a working one, but (presumably) due to the WAF on the forums its not letting me put it in a post, so I put it up as a Gist for you:
https://gist.github.com/Cameron-D/6962600
There was also another thread second from the top in this board with several other options: http://community.mybb.com/thread-113184.html
https://gist.github.com/Cameron-D/6962600
There was also another thread second from the top in this board with several other options: http://community.mybb.com/thread-113184.html