Here is a quick list of some of the recent developments from greater developer community. First is “deferred.defer” – Nick Johnson recently added a new module to App Engine Python SDK which allows you to use task queue service to execute deferred function calls. This library requires minimal configuration and makes it even easier to use tasks. Using it is as simple as calling deferred.defer with function and arguments you want to call. Other developments include: Ruby as a runtime option, TyphoonAE, gae-query-pager, AEJ Tools, An open source full text search library, Testing framework, Party Chat, and Other open source projects.
More info: Google App Engine blog