Three Main Roles
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There are basically three roles to be filled by organizers, which in theory could be done by one superhuman, but is more realistically split between two people.
First, the communicator. This includes publicizing the workshop on Meetup, works on getting more women to teach, and makes sure everyone knows where they're going and what they are required to show up with (XCode!!!). This role sends a lot of emails before the workshop, and is most visible to the students and teachers before the workshop happens.
Second, or the stage director (or logistics) role. This role includes stuff like planning food (if not handled by the venue), making sure the physical objects like extension cords and name tags get to the venue, and getting people signed in. There will probably be volunteers for any one of these tasks, but the stage director puts the volunteer there to do it.
Lastly is circus ringmistress, who welcomes everyone to the circus with an entertaining "what are we doing here" intro and sends people off to classes and be amazed by their own feats of strength. At the end this person inspires people to continue, with study groups and online resources, then points them to the after-party bar. (Our analogies sometimes break down.)
There's a technical requirement for the circus mistress because the presentations are maintained on Github and it's convenient if the circus master can clone and make pull requests as needed for their workshop. (Note, if you're a born circus-master but don't feel comfortable with git, we love git and always happily spread the good-git news.)
There are plenty of other things that could go into one person's bucket over the other. The three roles have more and less work at various points, so it might make sense for you to trade off being stage director before and during the weekend, in addition to your other role.
Mostly, talk to your co-organizer about their strengths, weaknesses, and what they want to do. Figure out how to have to most fun.