The most recent datastore for use on development is shared in Dropbox under a file called "current.sqlite".
To regenerate this file, start a dev appserver with a blank database, then navigate to:
(Substituting localhost:8080 for wherever your server is running).
Update June 2013: Starting the dev appserver with a blank database and navigating directly to http://localhost:8080 should result in a message under "Libraries" that says "There is no site content yet. Click here to import site content from live." Clicking the link will start populating the site (can take ~20 minutes).
Update July 2013: There are also these files available. The first is pretty clean, the second contains many students:
clean.sqlite full.sqlite [THESE MAY NOT BE MAINTAINED! See "Your first week: launching your test site!" for current.sqlite which will always be up to date]
These files were created with this import script:
If you get this error, try the following code in devshell:
from content import video_models
all = video_models.VideoLog.all()
for v in all:
v.key()._Key__reference.app_ = "dev~khan-academy"