Project codes of conduct
Many free software/open source projects have "codes of conduct" or other guidelines for how to act responsibly and respectfully.
One of the most famous is Ubuntu's "Code of Conduct." This page serves as an index of codes of conduct across all FLOSS projects.
Why these are useful
As a new contributor, you might prefer open source communities where contributors pay attention to these sorts of social questions. Having a code of conduct is often an indicator that a project has a sizeable number of contributors and interested in growing.
As a project maintainer, you might want to look these over as inspiration for your project.
This list is about open source projects, not in-person events. A good index for events is the Geek Feminism wiki, including its Event guidelines and their Conference anti-harassment section.
List
(feel free to add more, please preserve alphabetical order on project name)