I think that the Code of Conduct that Jeremy wrote is great. I like it so much, that if I ever do anything big enough to develop a community, this is what I would use.

~~~
== Ruby Community Code of Conduct (CoC) ==

This document provides community guidelines for a safe, respectful,
productive, and collaborative place for any person who is willing to
contribute to the Ruby community. It applies to all "collaborative
space", which is defined as community communications channels (such as
mailing lists, IRC, submitted patches, commit comments, etc.).

* Participants must ensure that their language and actions are free
of personal attacks and disparaging personal remarks.

* Participants who disrupt the collaborative space, or participate in a
pattern of behaviour which could be considered harassment will not be
tolerated.
~~~