Discontinued, see: fabianosoriani.wordpress.com/2011/06/02/leaving-google-appengine-for-rails-and-going-heroku
Woodie: gist.github.com/825451
Data types code.google.com/appengine/docs/java/datastore/entities.html#Properties_and_Value_Types
Lists (stackoverflow) stackoverflow.com/questions/1547601/app-engine-jruby-datamapper-list-property
Videocast building a blog www.youtube.com/watch?v=Oh9_t5W6MTE
Copying and batch Delete code.google.com/appengine/docs/adminconsole/datastoreadmin.html#Copying_Entities_to_Another_Application
-
Only 30 sec per request execution stackoverflow.com/questions/3355197/can-i-use-google-app-engine-for-processing-data