At YIMBYtown 2017 conference, attendees from [Greater Greater Washington, and ?] suggested organizing a recurring national phone call for YIMBY organizers.
Call dates and materials 
Weds November 29, 2017, 12pm PST. (1st call)
organized by Sarah Guidi at Greater Greater Washington. Email sguidi at ggwash.org to request meeting notes.
Weds, January 24, 2018, 12pm PST.
organized by Laura Bernstein (@YIMBYsea), and Tim McCormick of YIMBYwiki.
For meeting notes, email laura.ea.bernstein at gmail, or tmccormick at gmail.
Call #3 - February 
We're currently using Freeconference.com, free plan.
Agenda notes: for January call, organizers set up a Google Doc to propose and gather agenda, shared on YIMBYtown mailing list, and used same document for livenotes from any attendee during call. This seemed to work.