I can create a user and add a user to a role from the command line:
$ drush user-create organizer1
$ drush user-add-role organizer organizer1
There is no role named: organizer
However, I don't know how to create a role from the command line.
I found this module to modify the perms of a role:
http://drupal.org/project/drush_role
But still I am not able to find a way to create a role