The Super Customizable Iteration Chart app allows you to slice and dice burndown data into many types of views.
If you want to start using the app immediately, create an Custom HTML app on your Rally dashboard. Then copy App.html from the deploy folder into the HTML text area. That's it, it should be ready to use. See this help link if you don't know how to create a dashboard page for Custom HTML apps.
Or you can just click here to find the file and copy it into the custom HTML app.
Customization options include: stacked bar, grouped bar, line, or area display, story or task units, selectable colors, ideal lines, trend lines and any combination of schedule states.
You're free to customize this app to your liking (see the License section for details). Since this app uses a very old version of Rally's SDK, the app is only presented in its deployed form.
SuperCustomizableIterationChart is released under the MIT license. See the file LICENSE for the full text.