There are now two methods presented for quickly converting polygon shapefiles into a file that can be directly connected to by Tableau to create selectable polygon layers (Tableau Desktop 6.0 is needed for the selectable feature).
One option was developed for existing ArcGIS Users and is outlined in the Knowledge Base article Creating Tableau Polygons from ArcGIS Shapefiles
The other option was developed using Open Source code by own of our users, Joe Mako on map, shapefiles and points on February 14th (@Joe it would be great to repost your solution in this thread too)
Between the two methods and the options for selectable polygon features (see the Knowledge Base article Using Selectable Polygon Features in 6.0 for an example), I thought it would be great to start a thread to share what layers are available in a format readily importable by Tableau.
Many layers created by users are based on freely-available data, so for public-domain data it would be great to share what has already been created so others may use the data immediately. If there is a lot of data contributions we can pursue further organization of shared data as necessary. Using data blending capabilities in Tableau Desktop 6.0, the flexibility to extend the polygons with various types of attribute data from secondary data sources is made much easier.
Washington Zip Code Boundaries
To start, attached is a data source available for import into Tableau that is based on a polygon layer for Washington state using data from the U.S. Census Bureau (I did not include a sample workbook because it is included in the Knowledge Base articles listed above). Only the boundary information is included so you may join only the attributes needed for your analysis in Tableau.
British County Boundaries
The British County data set was created by Ty Alevizos here at Tableau. He also created an example workbook that shows how this data can be combined with demographic information for analysis inside Tableau (attached as britishcounties6.0.twbx).