My Google App Engine development website was taking a long time to load up. During my testing of the app, I kept uploading documents. After a few days of testing and developing the app, I had loaded several gigs of data into my dev server. It kept taking longer and longer to turn on.
I didn't need the data and this simple fix cleared my datastore and made the startup nice and snappy. You might want to occasionally do this if you notice a slow start up time.
dev_appserver.py --clear_datastore myapp