Shut Up & Write is a community that helps me commit to my (fiction) writing.

The format of my local meetup is as follows, and it works quite well:

1. Arrive, and socialize for 15 minutes
2. Shut up and write for 45 minutes
3. Socialize for 15 minutes
4. Shut up and write for 45 minutes

I attend the meetups often, but not every week.