LA Drupal now has an ladrupal-organizing mailing list. The list is unmoderated, publicly archived and any member of the Drupal community is welcome to sign up. This organizing list is intended for people who want to help organize LA Drupal events and activities and want an alternative to groups.drupal.org/la when doing it.
Everyone is still encouraged to use groups.drupal.org/la (especially for announcements, support questions, etc.), but with its erratic login system, a spam filter that sometimes acts possessed and a notifications system that sends messages without including message IDs that enable threading, it can sometimes be difficult to use this site for effective organizing within the group.
Eventually there might be a signup form on ladrupal.org (perhaps using the Lists module) but for now you can sign up directly at the ladrupal-organizing info page or just send a message to ladrupal-organizing-request AT ladrupal.org with "subscribe" in the subject line. If you'd like to become a list moderator or administrator, send a message to the list with your request or talk with any of the list moderators at one of the meetups.