Take the community-based elements of the community manager's role.
Growth, discussions, relationships, moderation, events/activities.
They're all linked.
You might host an event, create discussions about the event's topic to be reviews during the event. You might create content about the event. You might invite people to join the community who might be interested in the event (events are great growth/promotional tools) and you can invite members to help run/organize the event (relationships).
You might initiate a discussion based upon a major problem members face. You can make it a sticky thread and invite all members to give their opinion. You can create a poll based upon this and encourage members to write opinion/guest posts about the issue. You can invite outsiders to give their opinion on the issue.
Linking the activities creates a narrative. This is a narrative the community can follow. In addition, the entire community feels it has been through an experience together. This increases the sense of community amongst members.
The challenge then is planning these links in advance and successfullly executing them. Sounds obvious, but then you would be surprised...