Scrum/Tools

Open Atrium

Open Atrium provides a very good task-tracking tool called "Case Tracker". Case Tracker allows cases to be categorized (bug, feature, or task), assigned, and grouped into projects. Additionally, Case Tracker can send a notification to some or all team members when a case is updated.
Open Atrium is extremely customizable. Because Open Atrium is based on Drupal, it can even be extended with the thousands Drupal modules that already exist.
Like all Development Seed software, Open Atrium is extremely easy to use

Open Atrium's Case Tracker does not allow cases to be assigned to multiple team members. This can cause problems when two or more team members are to collaborate on one task, as only one of them see the task in her list of assigned tasks.
Though Open Atrium is very customizable, many customizations are wiped out whenever the system is upgraded. Though not impossible, building customizations in such a way that they do not interfere with future updates can be difficult and time-consuming.
As a beta product, Open Atrium has several design flaws. The notification system is especially problematic, often allowing users to spam one another unnecessarily.
The Case Tracker does not (by default) provide fields for time estimates or story points.
Open Atrium does not provide a burndown chart, and there do not seem to be any Drupal modules that can provide one

The bug dependency feature seems very useful. Scrum recognizes that a product cannot be fully defined from the start. As a result, Scrum encourages teams to write basic descriptions of distant requirements and add specific details as they become apparent. The bug dependency tool may allow for this.
- For example, a team building a website might create a user story for user login early in the project. Without much information, this story would be fairly high-level, for example "A user should be able to log into the site." Later, the team could add specific details as additional stories -- "A users should be able to log into the site with his email addresses", "The user should be able to find the 'Login' link in the top-right corner of the site", etc. These stories could depend on the first.
Mozilla is, of course, very familiar with Bugzilla. Most people would need little training with the tool.
The Songbird team has written a tool which generates reports from Bugzilla tickets. The tool, called SDPBOT, is released under an open-source license.

The authors of SDPBOT note that they "made no attempt to make it generic" and that people using the software should expect to "do some work to customize it" for their needs.
SDPBOT does not seem to generate burndown charts from Bugzilla data, and there do not seem to be any other tools that do.